Summary
Cloudflare Quiche: Use-after-free in connection ID iterator FFI functions
Impact
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 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.
Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.
CVE-2026-11941 has a CVSS score of 5.6 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.29.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-11941? CVE-2026-11941 is a medium-severity use after free vulnerability in quiche (rust), affecting versions >= 0.20.0, < 0.29.2. It is fixed in 0.29.2. Memory is accessed after it has been freed, leading to undefined behavior in native code.
- How severe is CVE-2026-11941? CVE-2026-11941 has a CVSS score of 5.6 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of quiche are affected by CVE-2026-11941? quiche (rust) versions >= 0.20.0, < 0.29.2 is affected.
- Is there a fix for CVE-2026-11941? Yes. CVE-2026-11941 is fixed in 0.29.2. Upgrade to this version or later.
- Is CVE-2026-11941 exploitable, and should I be worried? Whether CVE-2026-11941 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-11941 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-11941? Upgrade
quicheto 0.29.2 or later.