Improper validation of integrity check value in libssh - CVE-2026-59847
Published: July 27, 2026
Vulnerability identifier: #VU139530
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-59847
CWE-ID: CWE-354
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: libssh
Affected software:
libssh
libssh
Detailed vulnerability description
The vulnerability allows a remote attacker to modify plaintext transmitted over the connection without being detected.
The vulnerability exists due to improper integrity check in the OpenSSL AES-GCM backend when processing encrypted SSH traffic. A remote attacker can flip bits in packets in transit to modify plaintext transmitted over the connection without being detected.
Only OpenSSL-based server and client configurations using the affected AES-GCM ciphers are vulnerable. Successful exploitation requires knowledge of the expected plaintext format of the packets.
How to mitigate CVE-2026-59847
Install security update from vendor's website.