Description
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.
Published: 2026-06-17
Score: 9.2 Critical
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

No remediation available yet.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Thu, 18 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
Description 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.
Title libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
First Time appeared Libssh2
Libssh2 libssh2
Weaknesses CWE-680
CPEs cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*
Vendors & Products Libssh2
Libssh2 libssh2
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.2, 'vector': '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'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Subscriptions

Libssh2 Libssh2
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-06-18T11:46:01.897Z

Reserved: 2026-06-16T15:53:37.764Z

Link: CVE-2026-55200

cve-icon Vulnrichment

Updated: 2026-06-17T19:45:05.382Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-680

    Integer Overflow to Buffer Overflow