CVE-2025-5449: libssh Integer Overflow or Wraparound

Vulnerability summary

CVE-2025-5449 is a medium (CVSS 6.5) Integer Overflow or Wraparound vulnerability in libssh. EPSS estimates a 0.96% chance of exploitation in the next 30 days, higher than 60.7% of scored vulnerabilities.

Timeline

1. 25-07-2025
   PublishedVulnerability first disclosed.
2. 31-08-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in the SFTP server message decoding logic of libssh. The issue occurs due to an incorrect packet length check that allows an integer overflow when handling large payload sizes on 32-bit systems. This issue leads to failed memory allocation and causes the server process to crash, resulting in a denial of service.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.