CVE-2025-4877 MEDIUM

CVE-2025-4877: Libssh: write beyond bounds in binary to base64 conversion functions

Vendor Red Hat
Product Red Hat Enterprise Linux 10
Weakness CWE-787
Published August 20, 2025
Last update May 19, 2026

CVSS base score

4.5/10
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

What the vulnerability does

01Description

There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's possible that the program perform out of bounds write leading to a heap corruption. This issue affects only 32-bits builds of libssh.

Key dates

02Disclosure timeline

August 20, 2025 CVE published
May 19, 2026 Record updated