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📦 npm

GHSA-35p6-xmwp-9g52

LOW

undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

Also known asCVE-2026-6733
Published
Jun 19, 2026
Updated
Jun 21, 2026
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed

Blast Radius

3 pkgs affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

undicinpm
137.8Mdownloads / week

Description

Impact

Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.

This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.

Patches

Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.

Workarounds

Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
📦npmundiciall versions6.27.0
📦npmundici7.0.0&&< 7.28.07.28.0
📦npmundici8.0.0&&< 8.5.08.5.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for undici. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update undici to 6.27.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-35p6-xmwp-9g52 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-35p6-xmwp-9g52 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-35p6-xmwp-9g52. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Impact Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. ## Patches Upgrade to undici v6.27.0, v7.28.0 or v8.5.0. ## Workarounds
O3 Security · Impact-Aware SCA

Is GHSA-35p6-xmwp-9g52 in your dependencies?

O3 detects GHSA-35p6-xmwp-9g52 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.