Vulnerability Description
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Related Weaknesses (CWE)
References
- https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563
- https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0
- https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc
- https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d3
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
- https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8j
- https://github.com/libevent/libevent/security/advisories/GHSA-q39v-w2g7-gr8j
FAQ
What is CVE-2026-63382?
CVE-2026-63382 is a documented vulnerability. Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-En...
How severe is CVE-2026-63382?
CVSS scoring is not yet available for CVE-2026-63382. Check NVD for updates.
Is there a patch for CVE-2026-63382?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.