---
cve: "CVE-2026-63388"
severity: "HIGH"
cvss: 8.4
epss: "0.1%"
vendor: "libevent"
kev: false
exploited: false
published: "2026-08-20 18:16:36"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-28T12:59:55+02:00"
---

# CVE-2026-63388

> 8.4 HIGH · 🧪 PoC

## Beschreibung

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 79ddfb460847999b807cba76d04e73891f29c6ee (Commit)
- df3ecad3a040fd6d4fad4287defe113395de6fd7 (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-cvq5-vrvr-j338>
- <https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9>
- <https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72>
- <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-2026-63388) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_