CVE-2026-55200

libssh2 1.11.1, fixed in commit 97acf3d, 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 v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

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

Configurations

Configuration 1 (hide)

cpe:2.3:a:libssh2:libssh2:1.11.1:*:*:*:*:*:*:*

History

22 Oct 2026, 19:17

Type	Values Removed	Values Added
Summary	(en) 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.	(en) libssh2 1.11.1, fixed in commit 97acf3d, 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.

17 Sep 2026, 17:04

Type	Values Removed	Values Added
CPE	cpe:2.3:a:libssh2:libssh2::::::::	cpe:2.3:a:libssh2:libssh2:1.11.1:::::::*

Information

Published : 2026-06-17 20:17

Updated : 2026-10-22 19:17

NVD link : CVE-2026-55200

Mitre link : CVE-2026-55200

CVE.ORG link : CVE-2026-55200

JSON object : View

Products Affected

libssh2

libssh2

CWE

CWE-680

Integer Overflow to Buffer Overflow

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