Use-after-free in connection ID iterator and FFI functions

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Summary

CVECVE-2026-11941
StatePUBLISHED
Assignercloudflare
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-19 12:16:26 UTC
Updated2026-06-22 17:51:46 UTC
DescriptionCloudflare Quiche was affected by 2 use-after-free vulnerabilities in the connection ID iterator FFI functions. The “quiche_connection_id_iter_next” and “quiche_conn_retired_scid_next” functions would return a pointer to a “ConnectionId” to the applications via function arguments, but 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. Impact If unpatched, an application calling the affected FFI functions will dereference freed memory. The most likely outcome is undefined behavior leading to a process crash (denial of service). Depending on allocator state, the read may also return adjacent heap contents, resulting in limited information disclosure or incorrect connection identifier handling. Mitigation Users are requested to upgrade to quiche 0.29.2 which is the earliest version containing the fix for this issue.

Risk And Classification

Primary CVSS: v3.1 5.6 MEDIUM from [email protected]

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

EPSS: 0.001700000 probability, percentile 0.066250000 (date 2026-06-25)

Problem Types: CWE-416 | CWE-416 CWE-416 Use after free

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.6MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
3.1CNACVSS5.6MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Cloudflare Quiche affected 0.20.0 0.29.1 semver Not specified

References

ReferenceSourceLinkTags
github.com/cloudflare/quiche/security/advisories/GHSA-mh64-ph39-mrc9 [email protected] github.com
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