Quiche 0.29.2: UAF via Connection ID Iterator FFI
CVE-2026-11941 Published on June 19, 2026
Use-after-free in connection ID iterator and FFI functions
Cloudflare 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.
Vulnerability Analysis
CVE-2026-11941 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.
Weakness Type
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-11941 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-11941
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Affected Versions
Cloudflare Quiche:- Version 0.20.0, <= 0.29.1 is affected.