---
cve: "CVE-2026-63381"
severity: "MEDIUM"
cvss: 5.8
epss: "0.2%"
vendor: "libevent"
kev: false
exploited: false
published: "2026-08-20 18:16:35"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-05T03:13:27+02:00"
---

# CVE-2026-63381

> 5.8 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- df3ecad3a040fd6d4fad4287defe113395de6fd7 (Commit)
- 79ddfb460847999b807cba76d04e73891f29c6ee (Commit)

## BSI-Hinweise (deutsch)

- [Red Hat Enterprise Linux (corosync, libevent, libsoup): Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-3419) — _BSI-Einstufung: hoch_
  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.

## Referenzen

- <https://github.com/libevent/libevent/security/advisories/GHSA-c2pj-cg4r-88c8>
- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-63381) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_