Changelog

Source maps are now Generally Available (GA). You can now be uploaded with a maximum gzipped size of 15 MB. Previously, the maximum size limit was 15 MB uncompressed.

Source maps help map between the original source code and the transformed/minified code that gets deployed to production. By uploading your source map, you allow Cloudflare to map the stack trace from exceptions onto the original source code making it easier to debug.

With no source maps uploaded: notice how all the Javascript has been minified to one file, so the stack trace is missing information on file name, shows incorrect line numbers, and incorrectly references js instead of ts.

With source maps uploaded: all methods reference the correct files and line numbers.

Uploading source maps and stack trace remapping happens out of band from the Worker execution, so source maps do not affect upload speed, bundle size, or cold starts. The remapped stack traces are accessible through Tail Workers, Workers Logs, and Workers Logpush.

To enable source maps, add the following to your Pages Function's or Worker's wrangler configuration:

{
	"upload_source_maps": true
}

upload_source_maps = true

Update: Mon Mar 24th, 11PM UTC: Next.js has made further changes to address a smaller vulnerability introduced in the patches made to its middleware handling. Users should upgrade to Next.js versions 15.2.4, 14.2.26, 13.5.10 or 12.3.6. If you are unable to immediately upgrade or are running an older version of Next.js, you can enable the WAF rule described in this changelog as a mitigation.

Update: Mon Mar 24th, 8PM UTC: Next.js has now backported the patch for this vulnerability ↗︎ to cover Next.js v12 and v13. Users on those versions will need to patch to 13.5.9 and 12.3.5 (respectively) to mitigate the vulnerability.

Update: Sat Mar 22nd, 4PM UTC: We have changed this WAF rule to opt-in only, as sites that use auth middleware with third-party auth vendors were observing failing requests.

We strongly recommend updating your version of Next.js (if eligible) to the patched versions, as your app will otherwise be vulnerable to an authentication bypass attack regardless of auth provider.

This rule is opt-in only for sites on the Pro plan or above in the WAF managed ruleset.

To enable the rule:

1. Head to Security > WAF > Managed rules in the Cloudflare dashboard for the zone (website) you want to protect.
2. Click the three dots next to Cloudflare Managed Ruleset and choose Edit
3. Scroll down and choose Browse Rules
4. Search for CVE-2025-29927 (ruleId: 34583778093748cc83ff7b38f472013e)
5. Change the Status to Enabled and the Action to Block. You can optionally set the rule to Log, to validate potential impact before enabling it. Log will not block requests.
6. Click Next
7. Scroll down and choose Save

This will enable the WAF rule and block requests with the x-middleware-subrequest header regardless of Next.js version.

For users on the Free plan, or who want to define a more specific rule, you can create a Custom WAF rule to block requests with the x-middleware-subrequest header regardless of Next.js version.

To create a custom rule:

1. Head to Security > WAF > Custom rules in the Cloudflare dashboard for the zone (website) you want to protect.
2. Give the rule a name - e.g. next-js-CVE-2025-29927
3. Set the matching parameters for the rule match any request where the x-middleware-subrequest header exists per the rule expression below.

(len(http.request.headers["x-middleware-subrequest"]) > 0)

4. Set the action to 'block'. If you want to observe the impact before blocking requests, set the action to 'log' (and edit the rule later).
5. Deploy the rule.

We've made a WAF (Web Application Firewall) rule available to all sites on Cloudflare to protect against the Next.js authentication bypass vulnerability ↗︎ (CVE-2025-29927) published on March 21st, 2025.

Note: This rule is not enabled by default as it blocked requests across sites for specific authentication middleware.

• This managed rule protects sites using Next.js on Workers and Pages, as well as sites using Cloudflare to protect Next.js applications hosted elsewhere.
• This rule has been made available (but not enabled by default) to all sites as part of our WAF Managed Ruleset and blocks requests that attempt to bypass authentication in Next.js applications.
• The vulnerability affects almost all Next.js versions, and has been fully patched in Next.js 14.2.26 and 15.2.4. Earlier, interim releases did not fully patch this vulnerability.
• Users on older versions of Next.js (11.1.4 to 13.5.6) did not originally have a patch available, but this the patch for this vulnerability and a subsequent additional patch have been backported to Next.js versions 12.3.6 and 13.5.10 as of Monday, March 24th. Users on Next.js v11 will need to deploy the stated workaround or enable the WAF rule.

The managed WAF rule mitigates this by blocking external user requests with the x-middleware-subrequest header regardless of Next.js version, but we recommend users using Next.js 14 and 15 upgrade to the patched versions of Next.js as an additional mitigation.

Smart Placement is a unique Cloudflare feature that can make decisions to move your Worker to run in a more optimal location (such as closer to a database). Instead of always running in the default location (the one closest to where the request is received), Smart Placement uses certain “heuristics” (rules and thresholds) to decide if a different location might be faster or more efficient.

Previously, if these heuristics weren't consistently met, your Worker would revert to running in the default location—even after it had been optimally placed. This meant that if your Worker received minimal traffic for a period of time, the system would reset to the default location, rather than remaining in the optimal one.

Now, once Smart Placement has identified and assigned an optimal location, temporarily dropping below the heuristic thresholds will not force a return to default locations. For example in the previous algorithm, a drop in requests for a few days might return to default locations and heuristics would have to be met again. This was problematic for workloads that made requests to a geographically located resource every few days or longer. In this scenario, your Worker would never get placed optimally. This is no longer the case.

We're excited to introduce the Cloudflare Zero Trust Secure DNS Locations Write role, designed to provide DNS filtering customers with granular control over third-party access when configuring their Protective DNS (PDNS) solutions.

Many DNS filtering customers rely on external service partners to manage their DNS location endpoints. This role allows you to grant access to external parties to administer DNS locations without overprovisioning their permissions.

Secure DNS Location Requirements:

• Mandate usage of Bring your own DNS resolver IP addresses ↗︎ if available on the account.

• Require source network filtering for IPv4/IPv6/DoT endpoints; token authentication or source network filtering for the DoH endpoint.

You can assign the new role via Cloudflare Dashboard (Manage Accounts > Members) or via API. For more information, refer to the Secure DNS Locations documentation ↗︎.

A new GA release for the Android Cloudflare One Agent is now available in the Google Play Store ↗︎. This release includes a new feature allowing team name insertion by URL during enrollment, as well as fixes and minor improvements.

Changes and improvements

• Improved in-app error messages.
• Improved mobile client login with support for team name insertion by URL.
• Fixed an issue preventing admin split tunnel settings taking priority for traffic from certain applications.

A new GA release for the iOS Cloudflare One Agent is now available in the iOS App Store ↗︎. This release includes a new feature allowing team name insertion by URL during enrollment, as well as fixes and minor improvements.

Changes and improvements

• Improved in-app error messages.
• Improved mobile client login with support for team name insertion by URL.
• Bug fixes and performance improvements.

You can now access bindings from anywhere in your Worker by importing the env object from cloudflare:workers.

Previously, env could only be accessed during a request. This meant that bindings could not be used in the top-level context of a Worker.

Now, you can import env and access bindings such as secrets or environment variables in the initial setup for your Worker:

import { env } from "cloudflare:workers";
import ApiClient from "example-api-client";

// API_KEY and LOG_LEVEL now usable in top-level scope
const apiClient = ApiClient.new({ apiKey: env.API_KEY });
const LOG_LEVEL = env.LOG_LEVEL || "info";

export default {
	fetch(req) {
		// you can use apiClient or LOG_LEVEL, configured before any request is handled
	},
};

Additionally, env was normally accessed as a argument to a Worker's entrypoint handler, such as fetch. This meant that if you needed to access a binding from a deeply nested function, you had to pass env as an argument through many functions to get it to the right spot. This could be cumbersome in complex codebases.

Now, you can access the bindings from anywhere in your codebase without passing env as an argument:

// helpers.js
import { env } from "cloudflare:workers";

// env is *not* an argument to this function
export async function getValue(key) {
	let prefix = env.KV_PREFIX;
	return await env.KV.get(`${prefix}-${key}`);
}

For more information, see documentation on accessing env.

You can now retry your Cloudflare Pages and Workers builds directly from GitHub. No need to switch to the Cloudflare Dashboard for a simple retry!

Let\u2019s say you push a commit, but your build fails due to a spurious error like a network timeout. Instead of going to the Cloudflare Dashboard to manually retry, you can now rerun the build with just a few clicks inside GitHub, keeping you inside your workflow.

For Pages and Workers projects connected to a GitHub repository:

1. When a build fails, go to your GitHub repository or pull request
2. Select the failed Check Run for the build
3. Select "Details" on the Check Run
4. Select "Rerun" to trigger a retry build for that commit

Learn more about Pages Builds and Workers Builds.

Magic Firewall now supports a new managed list of Cloudflare IP ranges. This list is available as an option when creating a Magic Firewall policy based on IP source/destination addresses. When selecting "is in list" or "is not in list", the option "Cloudflare IP Ranges" will appear in the dropdown menu.

This list is based on the IPs listed in the Cloudflare IP ranges ↗︎. Updates to this managed list are applied automatically.

Note: IP Lists require a Cloudflare Advanced Network Firewall subscription. For more details about Cloudflare Network Firewall plans, refer to Plans.

We've released the next major version of Wrangler, the CLI for Cloudflare Workers — wrangler@4.0.0. Wrangler v4 is a major release focused on updates to underlying systems and dependencies, along with improvements to keep Wrangler commands consistent and clear.

You can run the following command to install it in your projects:

npm i wrangler@latest

yarn add wrangler@latest

pnpm add wrangler@latest

bun add wrangler@latest

Unlike previous major versions of Wrangler, which were foundational rewrites ↗︎ and rearchitectures ↗︎ — Version 4 of Wrangler includes a much smaller set of changes. If you use Wrangler today, your workflow is very unlikely to change.

A detailed migration guide is available and if you find a bug or hit a roadblock when upgrading to Wrangler v4, open an issue on the cloudflare/workers-sdk repository on GitHub ↗︎.

Going forward, we'll continue supporting Wrangler v3 with bug fixes and security updates until Q1 2026, and with critical security updates until Q1 2027, at which point it will be out of support.

You can now debug your Workers tests with our Vitest integration by running the following command:

vitest --inspect --no-file-parallelism

Attach a debugger to the port 9229 and you can start stepping through your Workers tests. This is available with @cloudflare/vitest-pool-workers v0.7.5 or later.

Learn more in our documentation.

You can now access environment variables and secrets on process.env when using the nodejs_compat compatibility flag.

const apiClient = ApiClient.new({ apiKey: process.env.API_KEY });
const LOG_LEVEL = process.env.LOG_LEVEL || "info";

In Node.js, environment variables are exposed via the global process.env object. Some libraries assume that this object will be populated, and many developers may be used to accessing variables in this way.

Previously, the process.env object was always empty unless written to in Worker code. This could cause unexpected errors or friction when developing Workers using code previously written for Node.js.

Now, environment variables, secrets, and version metadata can all be accessed on process.env.

To opt-in to the new process.env behaviour now, add the nodejs_compat_populate_process_env compatibility flag to your wrangler.json configuration:

{
	// Rest of your configuration
	// Add "nodejs_compat_populate_process_env" to your compatibility_flags array
	"compatibility_flags": ["nodejs_compat", "nodejs_compat_populate_process_env"],
	// Rest of your configuration

compatibility_flags = [ "nodejs_compat", "nodejs_compat_populate_process_env" ]

After April 1, 2025, populating process.env will become the default behavior when both nodejs_compat is enabled and your Worker's compatibility_date is after "2025-04-01".

Digital Experience Monitoring (DEX) provides visibility into device, network, and application performance across your Cloudflare SASE deployment. The latest release of the Cloudflare One agent (v2025.1.861) now includes device endpoint monitoring capabilities to provide deeper visibility into end-user device performance which can be analyzed directly from the dashboard.

Device health metrics are now automatically collected, allowing administrators to:

• View the last network a user was connected to
• Monitor CPU and RAM utilization on devices
• Identify resource-intensive processes running on endpoints

This feature complements existing DEX features like synthetic application monitoring and network path visualization, creating a comprehensive troubleshooting workflow that connects application performance with device state.

For more details refer to our DEX documentation.

Today, we are thrilled to announce Media Transformations, a new service that brings the magic of Image Transformations to short-form video files, wherever they are stored!

For customers with a huge volume of short video — generative AI output, e-commerce product videos, social media clips, or short marketing content — uploading those assets to Stream is not always practical. Sometimes, the greatest friction to getting started was the thought of all that migrating. Customers want a simpler solution that retains their current storage strategy to deliver small, optimized MP4 files. Now you can do that with Media Transformations.

To transform a video or image, enable transformations for your zone, then make a simple request with a specially formatted URL. The result is an MP4 that can be used in an HTML video element without a player library. If your zone already has Image Transformations enabled, then it is ready to optimize videos with Media Transformations, too.

https://example.com/cdn-cgi/media/<OPTIONS>/<SOURCE-VIDEO>

For example, we have a short video of the mobile in Austin's office. The original is nearly 30 megabytes and wider than necessary for this layout. Consider a simple width adjustment:

https://example.com/cdn-cgi/media/width=640/<SOURCE-VIDEO>
https://developers.cloudflare.com/cdn-cgi/media/width=640/https://middlecache.ced.cloudflare.com/v1/aus-mobile/aus-mobile.mp4

The result is less than 3 megabytes, properly sized, and delivered dynamically so that customers do not have to manage the creation and storage of these transformed assets.

For more information, learn about Transforming Videos.

We're excited to announce that new logging capabilities for Remote Browser Isolation (RBI) through Logpush are available in Beta starting today!

With these enhanced logs, administrators can gain visibility into end user behavior in the remote browser and track blocked data extraction attempts, along with the websites that triggered them, in an isolated session.

{
	"AccountID": "$ACCOUNT_ID",
	"Decision": "block",
	"DomainName": "www.example.com",
	"Timestamp": "2025-02-27T23:15:06Z",
	"Type": "copy",
	"UserID": "$USER_ID"
}

User Actions available:

• Copy & Paste
• Downloads & Uploads
• Printing

Learn more about how to get started with Logpush in our documentation.

Access for SaaS applications now include more configuration options to support a wider array of SaaS applications.

SAML and OIDC Field Additions

OIDC apps now include:

• Group Filtering via RegEx
• OIDC Claim mapping from an IdP
• OIDC token lifetime control
• Advanced OIDC auth flows including hybrid and implicit flows

SAML apps now include improved SAML attribute mapping from an IdP.

SAML transformations

SAML identities sent to Access applications can be fully customized using JSONata expressions. This allows admins to configure the precise identity SAML statement sent to a SaaS application.

You can now send detection logs to an endpoint of your choice with Cloudflare Logpush.

Filter logs matching specific criteria you have set and select from over 25 fields you want to send. When creating a new Logpush job, remember to select Email security alerts as the dataset.

For more information, refer to Enable detection logs.

This feature is available across these Email security packages:

• Enterprise
• Enterprise + PhishGuard

We've released a release candidate of the next major version of Wrangler, the CLI for Cloudflare Workers — wrangler@4.0.0-rc.0.

You can run the following command to install it and be one of the first to try it out:

npm i wrangler@v4-rc

yarn add wrangler@v4-rc

pnpm add wrangler@v4-rc

bun add wrangler@v4-rc

Unlike previous major versions of Wrangler, which were foundational rewrites ↗︎ and rearchitectures ↗︎ — Version 4 of Wrangler includes a much smaller set of changes. If you use Wrangler today, your workflow is very unlikely to change. Before we release Wrangler v4 and advance past the release candidate stage, we'll share a detailed migration guide in the Workers developer docs. But for the vast majority of cases, you won't need to do anything to migrate — things will just work as they do today. We are sharing this release candidate in advance of the official release of v4, so that you can try it out early and share feedback.

Version 4 of Wrangler updates the version of esbuild ↗︎ that Wrangler uses internally, allowing you to use modern JavaScript language features, including:

The using keyword from the Explicit Resource Management standard makes it easier to work with the JavaScript-native RPC system built into Workers. This means that when you obtain a stub, you can ensure that it is automatically disposed when you exit scope it was created in:

function sendEmail(id, message) {
  using user = await env.USER_SERVICE.findUser(id);
  await user.sendEmail(message);

  // user[Symbol.dispose]() is implicitly called at the end of the scope.
}

Import attributes ↗︎ allow you to denote the type or other attributes of the module that your code imports. For example, you can import a JSON module, using the following syntax:

import data from "./data.json" with { type: "json" };

All commands that access resources (for example, wrangler kv, wrangler r2, wrangler d1) now access local datastores by default, ensuring consistent behavior.

Moving forward, the active, maintenance, and current versions of Node.js ↗︎ will be officially supported by Wrangler. This means the minimum officially supported version of Node.js you must have installed for Wrangler v4 will be Node.js v18 or later. This policy mirrors how many other packages and CLIs support older versions of Node.js, and ensures that as long as you are using a version of Node.js that the Node.js project itself supports, this will be supported by Wrangler as well.

All previously deprecated features in Wrangler v2 ↗︎ and in Wrangler v3 ↗︎ have now been removed. Additionally, the following features that were deprecated during the Wrangler v3 release have been removed:

• Legacy Assets (using wrangler dev/deploy --legacy-assets or the legacy_assets config file property). Instead, we recommend you migrate to Workers assets ↗︎.
• Legacy Node.js compatibility (using wrangler dev/deploy --node-compat or the node_compat config file property). Instead, use the nodejs_compat compatibility flag ↗︎. This includes the functionality from legacy node_compat polyfills and natively implemented Node.js APIs.
• wrangler version. Instead, use wrangler --version to check the current version of Wrangler.
• getBindingsProxy() (via import { getBindingsProxy } from "wrangler"). Instead, use the getPlatformProxy() API ↗︎, which takes exactly the same arguments.
• usage_model. This no longer has any effect, after the rollout of Workers Standard Pricing ↗︎.

We'd love your feedback! If you find a bug or hit a roadblock when upgrading to Wrangler v4, open an issue on the cloudflare/workers-sdk repository on GitHub ↗︎.

Concerns about performance for Email security or Area 1? You can now check the operational status of both on the Cloudflare Status page ↗︎.

For Email security, look under Cloudflare Sites and Services.

• Dashboard is the dashboard for Cloudflare, including Email security
• Email security (Zero Trust) is the processing of email
• API are the Cloudflare endpoints, including the ones for Email security

For Area 1, under Cloudflare Sites and Services:

• Area 1 - Dash is the dashboard for Cloudflare, including Email security
• Email security (Area1) is the processing of email
• Area 1 - API are the Area 1 endpoints

This feature is available across these Email security packages:

• Advantage
• Enterprise
• Enterprise + PhishGuard

Cloudflare Email security customers who have Microsoft 365 environments can quickly deploy an Email DLP (Data Loss Prevention) solution for free.

Simply deploy our add-in, create a DLP policy in Cloudflare, and configure Outlook to trigger behaviors like displaying a banner, alerting end users before sending, or preventing delivery entirely.

Refer to Outbound Data Loss Prevention to learn more about this feature.

In GUI alert:

Alert before sending:

Prevent delivery:

This feature is available across these Email security packages:

• Enterprise
• Enterprise + PhishGuard

You can now interact with the Images API directly in your Worker.

This allows more fine-grained control over transformation request flows and cache behavior. For example, you can resize, manipulate, and overlay images without requiring them to be accessible through a URL.

The Images binding can be configured in the Cloudflare dashboard for your Worker or in the Wrangler configuration file in your project's directory:

{
	"images": {
		"binding": "IMAGES", // i.e. available in your Worker on env.IMAGES
	},
}

[images]
binding = "IMAGES"

Within your Worker code, you can interact with this binding by using env.IMAGES.

Here's how you can rotate, resize, and blur an image, then output the image as AVIF:

const info = await env.IMAGES.info(stream);
// stream contains a valid image, and width/height is available on the info object

const response = (
	await env.IMAGES.input(stream)
		.transform({ rotate: 90 })
		.transform({ width: 128 })
		.transform({ blur: 20 })
		.output({ format: "image/avif" })
).response();

return response;

For more information, refer to Images Bindings.

Small misconfigurations shouldn’t break your deployments. Cloudflare is introducing automatic error detection and fixes in Workers Builds, identifying common issues in your wrangler.toml or wrangler.jsonc and proactively offering fixes, so you spend less time debugging and more time shipping.

Here's how it works:

1. Before running your build, Cloudflare checks your Worker's Wrangler configuration file (wrangler.toml or wrangler.jsonc) for common errors.
2. Once you submit a build, if Cloudflare finds an error it can fix, it will submit a pull request to your repository that fixes it.
3. Once you merge this pull request, Cloudflare will run another build.

We're starting with fixing name mismatches between your Wrangler file and the Cloudflare dashboard, a top cause of build failures.

This is just the beginning, we want your feedback on what other errors we should catch and fix next. Let us know in the Cloudflare Developers Discord, #workers-and-pages-feature-suggestions ↗︎.

You can now locally configure your Magic WAN Connector to work in a static IP configuration.

This local method does not require having access to a DHCP Internet connection. However, it does require being comfortable with using tools to access the serial port on Magic WAN Connector as well as using a serial terminal client to access the Connector's environment.

For more details, refer to WAN with a static IP address.

Previously, all viewers watched "the live edge," or the latest content of the broadcast, synchronously. If a viewer paused for more than a few seconds, the player would automatically "catch up" when playback started again. Seeking through the broadcast was only available once the recording was available after it concluded.

Starting today, customers can make a small adjustment to the player embed or manifest URL to enable the DVR experience for their viewers. By offering this feature as an opt-in adjustment, our customers are empowered to pick the best experiences for their applications.

When building a player embed code or manifest URL, just add dvrEnabled=true as a query parameter. There are some things to be aware of when using this option. For more information, refer to DVR for Live.

You can now investigate links in emails with Cloudflare Security Center to generate a report containing a myriad of technical details: a phishing scan, SSL certificate data, HTTP request and response data, page performance data, DNS records, what technologies and libraries the page uses, and more.

From Investigation, go to View details, and look for the Links identified section. Select Open in Security Center next to each link. Open in Security Center allows your team to quickly generate a detailed report about the link with no risk to the analyst or your environment.

For more details, refer to Open links.

This feature is available across these Email security packages:

• Advantage
• Enterprise
• Enterprise + PhishGuard