CVE-2026-63385Libevent: HTTP header handling bugs create risk of access control bypass.
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.
- CVSS
- 9.2 CRITICAL (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N
- Weakness (CWE)
- CWE-444
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Aug 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
libevent libevent libevent:libevent (from the name) | from 2.2.0-alpha, < 2.2.2-alpha; before 2.1.13 | CNA record |
References
- https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2x-refsource-confirm
- https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0x-refsource-misc
- https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2x-refsource-misc
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stablex-refsource-misc
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alphax-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.