Name: CVE-2026-55200: Integer Overflow to Buffer Overflow
Creator: Rapid7
Published: 2026-06-17T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-55200, CWE-680, CVSS 8.1, EPSS 0.03877

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 Details

CVSS 4.0 Base Score: 9.2 (CRITICAL)
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
CVSS 3.1 Base Score: 8.1
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alpine Linux	—	Upgrade libssh2Upgrade chromium-rustUpgrade rust	Jun 24, 2026	Jun 17, 2026
Debian	—	Upgrade libssh2	Jul 23, 2026	Jul 23, 2026
Gentoo Linux	—	Upgrade net-libs/libssh2.	Aug 20, 2026	Aug 20, 2026
Redhat_linux	—	No solution exists	Jul 17, 2026	Jun 17, 2026
Ubuntu	—	Upgrade libssh2-1t64	Jun 30, 2026	Jun 17, 2026
Vmware Photon_os	—	Use 'tdnf update' to upgrade all packages to the latest version.	Jul 1, 2026	Jun 17, 2026

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CVSS Details

Covered by Rapid7

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