CVE catalog
CVE-2026-63381
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len
- Severity
- Critical · CVSS 9.2
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.16% · Oct 25, 2026
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. 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 |
| Ubuntu | libevent | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent-2.1-7t64 | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent-core-2.1-7t64 | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent-dev | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent-extra-2.1-7t64 | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent-openssl-2.1-7t64 | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent-pthreads-2.1-7t64 | noble | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent | pro | 2.1.8-stable-4build1 | vulnerable |
| Ubuntu | libevent | pro | 2.1.11-stable-1~exp0 | vulnerable |
| Ubuntu | libevent | pro | 2.1.11-stable-1 | vulnerable |
| Ubuntu | libevent | pro | 2.1.11-stable-1ubuntu0.1~esm1 | fixed |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1build1 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1build2 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1build3 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1ubuntu0.1 | fixed |
| Ubuntu | libevent | 24.04 | 2.1.12-stable-9 | vulnerable |
| Ubuntu | libevent | 24.04 | 2.1.12-stable-9ubuntu2 | vulnerable |
| Ubuntu | libevent | 24.04 | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent | 26.04 | 2.1.12-stable-10build1 | vulnerable |
| Ubuntu | libevent | 26.04 | 2.1.12-stable-10build2 | vulnerable |
| Ubuntu | libevent | 26.04 | 2.1.12-stable-10ubuntu0.1 | fixed |
| Ubuntu | libevent | pro | 2.1.8-stable-4build1 | vulnerable |
| Ubuntu | libevent | pro | 2.1.11-stable-1~exp0 | vulnerable |
| Ubuntu | libevent | pro | 2.1.11-stable-1 | vulnerable |
| Ubuntu | libevent | pro | 2.1.11-stable-1ubuntu0.1~esm1 | fixed |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1build1 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1build2 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1build3 | vulnerable |
| Ubuntu | libevent | 22.04 | 2.1.12-stable-1ubuntu0.1 | fixed |
| Ubuntu | libevent | 24.04 | 2.1.12-stable-9 | vulnerable |
| Ubuntu | libevent | 24.04 | 2.1.12-stable-9ubuntu2 | vulnerable |
| Ubuntu | libevent | 24.04 | 2.1.12-stable-9ubuntu2.1 | fixed |
| Ubuntu | libevent | 26.04 | 2.1.12-stable-10build1 | vulnerable |
| Ubuntu | libevent | 26.04 | 2.1.12-stable-10build2 | vulnerable |
| Ubuntu | libevent | 26.04 | 2.1.12-stable-10ubuntu0.1 | 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 |
| Ubuntu | libevent | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent-2.1-7t64 | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent-core-2.1-7t64 | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent-dev | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent-extra-2.1-7t64 | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent-openssl-2.1-7t64 | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent-pthreads-2.1-7t64 | deb | noble | 2.1.12-stable-9ubuntu2.1 | Not reported | Not reported | Not reported |
| Ubuntu | libevent | deb | pro | 2.1.11-stable-1ubuntu0.1~esm1 | Not reported | UBUNTU-CVE-2026-63381 | Not reported |
| Ubuntu | libevent | deb | 22.04 | 2.1.12-stable-1ubuntu0.1 | Not reported | UBUNTU-CVE-2026-63381 | Not reported |
| Ubuntu | libevent | deb | 24.04 | 2.1.12-stable-9ubuntu2.1 | Not reported | UBUNTU-CVE-2026-63381 | Not reported |
| Ubuntu | libevent | deb | 26.04 | 2.1.12-stable-10ubuntu0.1 | Not reported | UBUNTU-CVE-2026-63381 | Not reported |
| Ubuntu | libevent | deb | pro | 2.1.11-stable-1ubuntu0.1~esm1 | Not reported | USN-8710-1 | Not reported |
| Ubuntu | libevent | deb | 22.04 | 2.1.12-stable-1ubuntu0.1 | Not reported | USN-8710-1 | Not reported |
| Ubuntu | libevent | deb | 24.04 | 2.1.12-stable-9ubuntu2.1 | Not reported | USN-8710-1 | Not reported |
| Ubuntu | libevent | deb | 26.04 | 2.1.12-stable-10ubuntu0.1 | Not reported | USN-8710-1 | 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/5cb95ba2f804f8aff46f88d58391c71e1251cd1c]
- [https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9]
- [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-c2pj-cg4r-88c8]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-63381]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-63381]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-63381]
- [https://osv.dev/vulnerability/USN-8710-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-63381]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63381.json]
- [https://ubuntu.com/security/notices/USN-8710-1]
- [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] · [Ubuntu Security Notices (USN)]