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Fix CVE-2026-2229: override undici to ^6.24.0#203

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copilot/fix-undici-websocket-vulnerability
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Fix CVE-2026-2229: override undici to ^6.24.0#203
Copilot wants to merge 3 commits intomainfrom
copilot/fix-undici-websocket-vulnerability

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Copilot AI commented Apr 10, 2026

Transitive undici@5.29.0 (via @actions/core@actions/http-client) is vulnerable to DoS through invalid server_max_window_bits in the WebSocket permessage-deflate extension.

  • Added npm overrides to pin undici to ^6.24.0, resolving to 6.24.1 in the lock file
  • Chose overrides over upgrading @actions/core to v2+ (major version bump) since @actions/http-client only uses undici.ProxyAgent, which is API-compatible across v5→v6

Reachability: Not reachable (high confidence)

The vulnerability is in undici's WebSocket client. This codebase makes REST calls via Octokit only — no WebSocket usage. Update satisfies scanners.

Pre-existing test failures

inputs.test.ts (3 tests) and secretscanning.test.ts (suite) fail before and after this change — unrelated to this update.

Original prompt

This section details the Dependabot vulnerability alert you should resolve

<alert_title>Undici has Unhandled Exception in WebSocket Client Due to Invalid server_max_window_bits Validation</alert_title>
<alert_description>### Impact

The undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination.

The vulnerability exists because:

  1. The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15
  2. The createInflateRaw() call is not wrapped in a try-catch block
  3. The resulting exception propagates up through the call stack and crashes the Node.js process

Patches

Has the problem been patched? What versions should users upgrade to?

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?</alert_description>

high
GHSA-v9p9-hfj2-hcw8, CVE-2026-2229
undici
npm
<vulnerable_versions>5.29.0</vulnerable_versions>
<patched_version>6.24.0</patched_version>
<manifest_path>package-lock.json</manifest_path>

https://github.com/nodejs/undici/security/advisories/GHSA-v9p9-hfj2-hcw8 https://nvd.nist.gov/vuln/detail/CVE-2026-2229 https://hackerone.com/reports/3487486 https://cna.openjsf.org/security-advisories.html https://datatracker.ietf.org/doc/html/rfc7692 https://nodejs.org/api/zlib.html#class-zlibinflateraw https://github.com/advisories/GHSA-v9p9-hfj2-hcw8

<task_instructions>Resolve this alert by updating the affected package to a non-vulnerable version. Prefer the lowest non-vulnerable version (see the patched_version field above) over the latest to minimize breaking changes. Include a Reachability Assessment section in the PR description. Review the alert_description field to understand which APIs, features, or configurations are affected, then search the codebase for usage of those specific items. If the vulnerable code path is reachable, explain how (which files, APIs, or call sites use the affected functionality) and note that the codebase is actively exposed to this vulnerability. If the vulnerable code path is not reachable, explain why (e.g. the affected API is never called, the vulnerable configuration is not used) and note that the update is primarily to satisfy vulnerability scanners rather than to address an active risk. If the advisory is too vague to determine reachability (e.g. 'improper input validation' with no specific API named), state that reachability could not be determined and explain why. Include a confidence level in the reachability assessment (e.g. high confidence if the advisory names a specific API and you confirmed it is or is not called, low confidence if the usage is indirect and hard to trace). If no patched version is available, check the alert_description field for a Workarounds section — the advisory may describe configuration changes or usage patterns that mitigate the vulnerability without a version update. If a workaround is available, apply it and leave a code comment referencing the advisory identifier explaining it is a temporary mitigation. If neither a patch nor a workaround is available, explain in the PR description why the alert cannot be resolved automatically so a human reviewer can take over. Inspect the repository to determine which package manager is used (e.g. lock files, config files, build scripts) and use that tooling to perform the update — do not edit lock files directly. If the version constraint in the manifest (e.g. package.json, Gemfile, pyproject.toml) caps the version below the fix, update the constraint first. For transitive dependencies, determine whether it is simpler to update the direct dependency that pulls in the vulnerable package or to update the transitive dependency directly, and choose the least disruptive approach. If upgrading to fix the vulnerability forces a major version bump or known breaking changes, review the changelog or release notes, then audit the codebase for usage of affected APIs and fix any breaking changes that are found. If the package manager fails to resolve dependencies (e.g. peer dependency conflicts, incompatible engine constraints), document the error in the PR description rather than attemp...

Copilot AI changed the title [WIP] Fix unhandled exception in undici WebSocket client Fix CVE-2026-2229: override undici to ^6.24.0 Apr 10, 2026
Copilot AI requested a review from felickz April 10, 2026 16:47
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