CVE-2026-11941
CWE-416Published: June 19, 2026· Updated: Jun 22, 2026
Official Description
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.
Technical Analysis
CVE-2026-11941 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
From a weakness classification perspective (CWE-416): Use-after-free vulnerabilities involve accessing memory after it has been freed, often enabling arbitrary code execution.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (1)
Quick Facts
Related CVEs (CWE-416)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-11941 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts