CVE-2026-55200

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.

Affected products

Linuxmint, Libssh2

libssh2

≤ 1.11.1

Fix

Available

CVSS 4.0

9.2 CRITICAL

CVSS 3.1

8.3 HIGH

EPSS

2.0% (79th percentile)

Weakness

CWE-680

NVD status

Analyzed

Published

2026-06-17