CVE catalog
CVE-2026-63495
Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a to
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Updated
- Source
- [NVD] · [CVE record]
- EPSS
- 0.61% · Oct 25, 2026
Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a total message-size limit. An unauthenticated remote client can repeatedly send fragmented WebSocket frames below WS_MAX_RECV_FRAME_SZ with FIN=0, causing the evbuffer to grow without bound until the process or host exhausts memory. This issue is fixed in version 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 | not affected |
| Debian | libevent | forky | 2.1.13-stable-1 | not affected |
| Debian | libevent | trixie | 2.1.12-stable-10 | not affected |
| Debian | libevent | trixie-security | 2.1.13-stable-1~deb13u1 | not affected |
| Debian | libevent | bookworm | 2.1.12-stable-8 | not affected |
| Debian | libevent | bookworm-security | 2.1.12-stable-8+deb12u1 | not affected |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | libevent | source | sid | Not affected | unimportant | Not reported | Not reported |
| Debian | libevent | source | forky | Not affected | unimportant | Not reported | Not reported |
| Debian | libevent | source | trixie | Not affected | unimportant | Not reported | Not reported |
| Debian | libevent | source | bookworm | Not affected | unimportant | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libevent-2.1-7]Not affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormNot affected
nvd · libevent · debian · bookworm
2.1.12-stable-8· arm64 · bookwormNot affected
nvd · libevent · debian · bookworm
- [libevent-core-2.1-7]Not affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormNot affected
nvd · libevent · debian · bookworm
2.1.12-stable-8· arm64 · bookwormNot affected
nvd · libevent · debian · bookworm
- [libevent-dev]Not affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormNot affected
nvd · libevent · debian · bookworm
2.1.12-stable-8· arm64 · bookwormNot affected
nvd · libevent · debian · bookworm
- [libevent-extra-2.1-7]Not affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormNot affected
nvd · libevent · debian · bookworm
2.1.12-stable-8· arm64 · bookwormNot affected
nvd · libevent · debian · bookworm
- [libevent-openssl-2.1-7]Not affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormNot affected
nvd · libevent · debian · bookworm
2.1.12-stable-8· arm64 · bookwormNot affected
nvd · libevent · debian · bookworm
- [libevent-pthreads-2.1-7]Not affected
Source package: [libevent]
Details (2)
2.1.12-stable-8· amd64 · bookwormNot affected
nvd · libevent · debian · bookworm
2.1.12-stable-8· arm64 · bookwormNot affected
nvd · libevent · debian · bookworm
Observed:
References
- [https://github.com/libevent/libevent/commit/291c4d1cd75695e898030ebd5c4ddf26c094077b]
- [https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha]
- [https://github.com/libevent/libevent/security/advisories/GHSA-qx89-wf2v-vgmx]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-63495]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-63495]
- [https://security-tracker.debian.org/tracker/CVE-2026-63495]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63495.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]