Cloudflare Quiche: Use-after-free in connection ID iterator FFI functions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.6 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS

• CVE-2026-11941: 0.25% estimated exploitation activity in the next 30 days; percentile 16.52 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Cloudflare Quiche was affected by 2 use-after-free vulnerabilities in the connection ID iterator FFI functions. The quicheconnectioniditernext and quicheconnretiredscidnext functions would return a pointer to a ConnectionId to the applications via function arguments, but the the owned ConnectionId would be dropped at the end of those functions' scope. Only applications using those FFI functions are affected. The FFI API is disabled by default by a build-time feature flag. quiche 0.29.2 is the earliest version containing the fix for this issue.

Published by the source

19 Jun 2026, 22:10 UTC

Last modified by the source

19 Jun 2026, 22:10 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mh64-ph39-mrc9

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# Patch Next advisory brief: CVE-2026-11941

Advisory: Cloudflare Quiche: Use-after-free in connection ID iterator FFI functions
IDs: CVE-2026-11941, GHSA-mh64-ph39-mrc9
Record: https://patchnext.com/advisories/cve-2026-11941 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: quiche 0.29.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io quiche: affected >= 0.20.0, < 0.29.2; fixed in 0.29.2

## Suggested inspection (read-only)
- crates.io quiche: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on quiche.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mh64-ph39-mrc9 (GitHub-reviewed advisory GHSA-mh64-ph39-mrc9 lists affected ranges: crates.io quiche >=0.20.0 <0.29.2)

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