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fix(network): enforce URL policy across redirects by mcc0nnell · Pull Request #2767 · ChromeDevTools/chrome-devtools-mcp · GitHub
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fix(network): enforce URL policy across redirects - #2767

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OrKoN merged 4 commits into
ChromeDevTools:mainfrom
mcc0nnell:ihb/resource-redirect-policy
Oct 13, 2026
Merged

OrKoN merged 4 commits into
ChromeDevTools:mainfrom
mcc0nnell:ihb/resource-redirect-policy

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Summary

  • enforce allowedUrlPattern / blockedUrlPattern on every HTTP redirect hop in the Node-side DevTools resource loader
  • follow redirects manually instead of letting fetch() follow them after a single initial policy check
  • reject redirects to unsupported schemes and retain a bounded redirect limit
  • add coverage for disallowed final destinations, blocked intermediate hops, and valid all-allowed chains

Why

McpContext.loadResource() currently validates the URL supplied by DevTools and then calls fetch(url). Node fetch follows redirects by default, so later redirect destinations are not checked against the configured URL policy.

This loader is wired into McpHostBindingAdapter.loadNetworkResource() and DevTools PageResourceLoader, including source-map loading. That means an allowed resource URL can redirect the Node-side loader to a destination excluded by the configured allowlist/blocklist.

A loopback-only before/after proof used an allowed server that returned a 302 to a forbidden server:

Before this patch:

BEFORE {"result":"returned","body":"IHB_REDIRECT_CANARY_31337","forbiddenHits":1}

With this patch:

AFTER {"result":"threw","message":"Not allowed by allowlist: http://127.0.0.1:<port>/secret","forbiddenHits":0}

The policy is therefore enforced before the redirected destination is requested or its body is consumed.

Implementation

The network resource loader now uses redirect: 'manual' and, for each hop:

  1. checks the blocklist
  2. checks the allowlist
  3. performs the request
  4. resolves a redirect Location relative to the current URL
  5. rejects non-HTTP(S) redirect targets
  6. repeats with a bounded redirect count

Normal non-redirect responses keep the existing behavior.

Verification

  • redirect outside allowlist: pass
  • redirect into blocklist: pass
  • blocked intermediate redirect: pass
  • all redirect hops allowed: pass
  • ESLint: pass
  • Prettier: pass
  • TypeScript typecheck: pass
  • git diff --check: pass

Commit is signed and includes a DCO Signed-off-by trailer.

Related context: #2567 describes a separate Lighthouse-owned secondary-fetch redirect path. This change is specifically for the Node-side DevTools resource loader used through McpHostBindingAdapter / PageResourceLoader.

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As documented the allowlist and block list are for the browser process and we generally should not be event validating MCP server's internal network requests, but since we already do it would be fine to extend to redirects to avoid AI "finding" all over again. Could you please rebase? cc @Lightning00Blade

Signed-off-by: Robert McConnell <robert@mcc0nnell.org>
@mcc0nnell
mcc0nnell force-pushed the ihb/resource-redirect-policy branch from 0cd9323 to b220ed7 Compare October 2, 2026 12:43
@mcc0nnell

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Rebased onto current main. I also updated the new test helper to the current allowlist option name that changed upstream. npm run build passes and the four focused redirect-policy tests pass. Ready for another look.

@Lightning00Blade
Lightning00Blade self-requested a review October 13, 2026 12:14
Comment thread src/McpContext.ts Resolved
@OrKoN
OrKoN enabled auto-merge October 13, 2026 14:13
@OrKoN
OrKoN added this pull request to the merge queue Oct 13, 2026
Merged via the queue into ChromeDevTools:main with commit 274cd4c Oct 13, 2026
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OrKoN added a commit that referenced this pull request Oct 15, 2026
🤖 I have created a release *beep* *boop*
---


##
[1.11.0](chrome-devtools-mcp-v1.10.1...chrome-devtools-mcp-v1.11.0)
(2026-10-15)


### 🎉 Features

* add --file-navigations flag to reject file: URL navigations
([#2853](#2853))
([54cae57](54cae57))
* Add analyze_heapsnapshot_contexts MCP tool
([#2791](#2791))
([190aeee](190aeee))
* add ignoreCache option to performance_start_trace
([#2931](#2931))
([3467d40](3467d40))
* add maxNameLength truncation option to compare_heapsnapshots
([#3098](#3098))
([1e1c53e](1e1c53e))
* Add pagination to compare_heapsnapshots
([#3140](#3140))
([daebfd1](daebfd1))
* **config:** add ConfigWatcher to watch config file changes
([#3139](#3139))
([9171f77](9171f77))
* discover the config file in predefined locations
([#2876](#2876))
([02c0112](02c0112))
* implement ffmpeg-free screencast tools enabled by default
([#3123](#3123))
([8953ea5](8953ea5))
* reduce StaticText noise in text snapshots
([#2895](#2895))
([4441325](4441325))
* report pages opened by input actions
([#2679](#2679))
([28fb230](28fb230))
* resolve config defaults after merging CLI and config file
([#2849](#2849))
([bdeb70d](bdeb70d))
* return failing audits and DOM nodes inline from lighthouse_audit
([#2930](#2930))
([241fba5](241fba5))
* skip more redundant data in text snapshots
([#2896](#2896))
([b2f522c](b2f522c))
* support debugging WebMCP tools in third-party developer tools
([#2900](#2900))
([0db519f](0db519f))
* support emulating additional CSS media features
([#2929](#2929))
([69524f0](69524f0))
* support evaluating scripts from local files
([#2606](#2606))
([9cf47a4](9cf47a4))
* Support truncation in get_heapsnapshot_details
([#3137](#3137))
([f827e06](f827e06))
* Truncate long names by default to 100 characters
([#2893](#2893))
([5ddb0a3](5ddb0a3))


### 🛠️ Fixes

* account for scroll offsets in downscaled screenshots
([#2685](#2685))
([830c693](830c693))
* allow --categoryExtensions when connecting to an existing browser
([#3041](#3041))
([d250bc5](d250bc5))
* allow stopping the CLI if command fails
([#3088](#3088))
([77e238e](77e238e)),
closes
[#2982](#2982)
* avoid runtime title fetches
([#2883](#2883))
([04195d1](04195d1))
* better config support for chrome-devtools CLI
([#2819](#2819))
([9624e64](9624e64))
* clamp async stack trace separator repeat count
([#3035](#3035))
([93e06ab](93e06ab)),
closes
[#3031](#3031)
* **cli:** pass positional values starting with `-` through to tools
([#3084](#3084))
([9de05ae](9de05ae)),
closes
[#2984](#2984)
* **collectors:** ignore transient target errors when subscribing to
service workers
([#2888](#2888))
([551dd6c](551dd6c))
* **daemon:** bound browser shutdown and avoid watchFile timeout on stop
([#2887](#2887))
([f3db5e7](f3db5e7))
* **daemon:** keep fallback socket in private runtime dir
([#2766](#2766))
([871a37e](871a37e))
* **daemon:** verify process identity before treating PID file as active
([#3109](#3109))
([b608bed](b608bed))
* do not close a healthy browser when a tool call outlasts 60s
([#3149](#3149))
([39c7db1](39c7db1))
* ensure aggregate IDs in heap snapshots are deterministic
([#2923](#2923))
([e918c47](e918c47))
* escape client-supplied values in McpContext logs and errors
([#2832](#2832))
([efb0d02](efb0d02)),
closes
[#2831](#2831)
* fail fast on tool calls stuck after a dead browser connection
([#2699](#2699))
([2a7ef50](2a7ef50))
* harden third-party tool result serialization
([#2892](#2892))
([4418a7b](4418a7b))
* honor explicit --allowUnrestrictedPaths=false in CLI mode
([#3040](#3040))
([61fc362](61fc362))
* include errors in slim responses
([#3085](#3085))
([ee38097](ee38097))
* **input:** reject multiple file paths on single-file input in
upload_file
([#2995](#2995))
([#3135](#3135))
([e650843](e650843))
* list fresh page titles
([#3103](#3103))
([e717082](e717082))
* **memory:** reject contradictory pagination options in
take_heapsnapshot
([#3002](#3002))
([#3131](#3131))
([508126c](508126c))
* **network:** enforce URL policy across redirects
([#2767](#2767))
([274cd4c](274cd4c))
* pass categoryExtensions to the target filter when connecting
([#3047](#3047))
([4e90238](4e90238))
* **performance:** report an error when performance_stop_trace is called
with no active trace
([#3001](#3001))
([#3126](#3126))
([e170384](e170384))
* preserve HeapSnapshotManager across browser reconnects
([#3025](#3025))
([64388c6](64388c6))
* propagate failed responseFilePath write error instead of reporting
body unavailable
([#2957](#2957))
([#3119](#3119))
([3cee3bd](3cee3bd))
* **pwa:** wait for initial navigation on launch and retry transient
install error
([#2889](#2889))
([63010cb](63010cb))
* record screencast at the page's device pixel size
([#3155](#3155))
([62e2aa4](62e2aa4))
* reject --blockedUrlPattern/--allowedUrlPattern hostname regexp groups
([#2796](#2796))
([ae0aaef](ae0aaef))
* reject JSON arrays as 3p and WebMCP tool params
([#2785](#2785))
([c14e616](c14e616))
* reject named groups in URL patterns
([#2857](#2857))
([5b2c6f9](5b2c6f9))
* reject non-positive --viewport dimensions
([#2781](#2781))
([0ef528a](0ef528a))
* reject non-positive resize_page dimensions
([#2784](#2784))
([6ab6d35](6ab6d35))
* reject unrestricted paths with an explicit workspace
([#2858](#2858))
([45c1c6c](45c1c6c))
* report unknown page id before last-page guard in close_page
([#3042](#3042))
([bdc7e24](bdc7e24))
* round lighthouse category scores and show unscored categories as n/a
([#2924](#2924))
([7007680](7007680)),
closes
[#2915](#2915)
[#2916](#2916)
* set empty filePath to undefined instead of empty string
([#2836](#2836))
([adfc1ff](adfc1ff)),
closes
[#2825](#2825)
* surface WebMCP tool exceptions in execute_webmcp_tool
([#3107](#3107))
([d80d22e](d80d22e)),
closes
[#2975](#2975)
* url pattern partial ipv4
([#2859](#2859))
([c87d190](c87d190))


### 📄 Documentation

* clarify Antigravity MCP setup for VS Code extension
([#2855](#2855))
([12e13ca](12e13ca))
* clarify scope of --no-javascript-evaluation
([#3100](#3100))
([0c67cd5](0c67cd5))
* correct link to configuration
([#3086](#3086))
([bbb1e36](bbb1e36))
* document trusted host environment in SECURITY.md
([#3125](#3125))
([1352207](1352207))
* fix inaccurate examples in skills and CLI docs
([#2922](#2922))
([ec372b0](ec372b0)),
closes
[#2906](#2906)
[#2907](#2907)
[#2908](#2908)
[#2910](#2910)
[#2912](#2912)
[#2913](#2913)
[#2918](#2918)
[#2919](#2919)
[#2920](#2920)
[#2921](#2921)
* fix some reported issues
([#3099](#3099))
([d5d2f08](d5d2f08))
* include serviceWorkerId parameter for evaluate_script
([#3015](#3015))
([#3129](#3129))
([0623434](0623434))
* mention heapsnapshot being cached between runs
([#3045](#3045))
([f08dbe1](f08dbe1)),
closes
[#2976](#2976)
* **skills:** remove invalid outputDir flag from lighthouse_audit calls
([#3013](#3013))
([#3130](#3130))
([7754226](7754226))
* update documentation and SKILL for get_css_styles tool
([#2824](#2824))
([3c12a91](3c12a91))


### ⚡ Performance

* **cli:** re-use MCPServer.from helpers for daemon
([#2804](#2804))
([89eb3d5](89eb3d5))
* Load heap snapshots in parallel in compare_heapsnapshots
([#3023](#3023))
([20c1391](20c1391))


### 🏗️ Refactor

* centralize config defaults and conflict checks
([#2753](#2753))
([a739ba8](a739ba8))
* create all tools and register per slim mode
([#2874](#2874))
([99847a7](99847a7))
* enable categories by default
([#2811](#2811))
([e33ee48](e33ee48))
* extract CLI examples and conflict list in mcp-options
([#2848](#2848))
([45000d9](45000d9))
* extract config parsing logic in a class
([#2861](#2861))
([e4168d0](e4168d0))
* extract worker logic into McpWorker
([#2800](#2800))
([77165c6](77165c6))
* group Puppeteer and tool options
([#2875](#2875))
([699c4d5](699c4d5))
* lazily initialize McpPage from Target and enumerate targets in
McpContext
([#2812](#2812))
([545cbe3](545cbe3))
* use default Error for toolSchema
([#2822](#2822))
([8b2768d](8b2768d))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Co-authored-by: Alex Rudenko <OrKoN@users.noreply.github.com>
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3 participants