CVE catalog
CVE-2026-63379
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix
- Severity
- Medium · CVSS 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.71% · Oct 25, 2026
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | libevent | sid | 2.1.13-stable-1 | fixed |
| Debian | libevent | forky | 2.1.13-stable-1 | fixed |
| Debian | libevent | trixie | 2.1.12-stable-10 | vulnerable |
| Debian | libevent | trixie-security | 2.1.13-stable-1~deb13u1 | fixed |
| Debian | libevent | bookworm | 2.1.12-stable-8 | vulnerable |
| Debian | libevent | bookworm-security | 2.1.12-stable-8+deb12u1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | libevent | source | sid | 2.1.13-stable-1 | not yet assigned | Not reported | Not reported |
| Debian | libevent | source | forky | 2.1.13-stable-1 | not yet assigned | Not reported | Not reported |
| Debian | libevent | source | trixie | 2.1.13-stable-1~deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | libevent | source | bookworm | 2.1.12-stable-8+deb12u1 | not yet assigned | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libevent-2.1-7]Affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
2.1.12-stable-8· arm64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
- [libevent-core-2.1-7]Affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
2.1.12-stable-8· arm64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
- [libevent-dev]Affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
2.1.12-stable-8· arm64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
- [libevent-extra-2.1-7]Affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
2.1.12-stable-8· arm64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
- [libevent-openssl-2.1-7]Affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
2.1.12-stable-8· arm64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
- [libevent-pthreads-2.1-7]Affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
2.1.12-stable-8· arm64 · bookwormAffected · Fixed:
2.1.12-stable-8+deb12u1nvd · libevent · debian · bookworm; nvd · libevent · debian · 12
[Debian 13 (Trixie)]
- [libevent-2.1-7t64]Affected
Source package: [libevent]
Details (3)
2.1.12-stable-10+b1· amd64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.12-stable-10+b1· arm64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.13-stable-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
- [libevent-core-2.1-7t64]Affected
Source package: [libevent]
Details (3)
2.1.12-stable-10+b1· amd64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.12-stable-10+b1· arm64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.13-stable-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
- [libevent-dev]Affected
Source package: [libevent]
Details (3)
2.1.12-stable-10+b1· amd64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.12-stable-10+b1· arm64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.13-stable-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
- [libevent-extra-2.1-7t64]Affected
Source package: [libevent]
Details (3)
2.1.12-stable-10+b1· amd64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.12-stable-10+b1· arm64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.13-stable-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
- [libevent-openssl-2.1-7t64]Affected
Source package: [libevent]
Details (3)
2.1.12-stable-10+b1· amd64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.12-stable-10+b1· arm64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.13-stable-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
- [libevent-pthreads-2.1-7t64]Affected
Source package: [libevent]
Details (3)
2.1.12-stable-10+b1· amd64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.12-stable-10+b1· arm64 · trixieAffected · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
2.1.13-stable-1~deb13u1· amd64 · trixie-securityFixed · Fixed:
2.1.13-stable-1~deb13u1nvd · libevent · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/rhsa-2026_67909.json]
- [https://github.com/libevent/libevent/commit/87e8e44fa774e9677b089b1a5114ee68aefa1636]
- [https://github.com/libevent/libevent/commit/b847071141b3827900d536594ec9045eb0a4c485]
- [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-2gmv-p5m7-98p6]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-63379]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-63379]
- [https://security-tracker.debian.org/tracker/CVE-2026-63379]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63379.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-3419.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]