---
cve: "CVE-2026-55200"
severity: "CRITICAL"
cvss: 9.2
epss: "2%"
vendor: "libssh2"
kev: false
exploited: false
published: "2026-06-17 20:17:28"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-04T01:54:46+02:00"
---

# CVE-2026-55200

> 9.2 CRITICAL · 🧪 PoC

## Beschreibung

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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)

- 97acf3dfda80c91c3a8c9f2372546301d4a1a7a8 (Commit)

## Referenzen

- <https://github.com/libssh2/libssh2/pull/2052>
- <https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8>
- <https://www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-c>
- <https://web.archive.org/web/20260623211210/https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-poc>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-55200) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_