CVE-2026-63382
criticalpriority · track · 0EPSS 0.008 · 56 %ileDEFRRUEPSS · scored 2026-10-28
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.1–9.4
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (18)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-3419Red Hat Enterprise Linux (corosync, libevent, libsoup): Mehrere SchwachstellenDeutsch2026-09-16csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Red Hat Enterprise Linux ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder offenzulegen oder Denial-of-Service-Zustände herbeizuführen.
- CERTFR-2026-AVI-1336Multiples vulnérabilités dans les produits IBMFrançais2026-10-16vendor · certfrFR
- CERTFR-2026-AVI-1378Multiples vulnérabilités dans les produits IBMFrançais2026-10-23vendor · certfrFR
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (7) nvd
External citations — patches, advisories, analysis.
- https://github.com/libevent/libevent/commit/10abb34b8dc3e1184de315dd261ce4b77563cda6
- https://github.com/libevent/libevent/commit/5119ceb00557bf007f9065709e852686f3c0bb6e
- https://github.com/libevent/libevent/commit/83ba67373032334559b82409db035dd8c3cc1660
- https://github.com/libevent/libevent/commit/ac38703b2d312200c4f967f02936af0118d384a0
- 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
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