---
cve: "CVE-2026-63383"
severity: "HIGH"
cvss: 8.7
epss: "0.4%"
vendor: "libevent"
kev: false
exploited: false
published: "2026-08-20 18:16:35"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-27T14:25:27+02:00"
---

# CVE-2026-63383

> 8.7 HIGH · 🧪 PoC

## Beschreibung

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. 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: **poc**
  - Automatable: **yes**
  - Technical Impact: **partial**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| 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-fj29-64w6-73h6>
- <https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321>
- <https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb>
- <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-2026-63383) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_