CVE-2025-4877: Memory Corruption (CVSS 4.5)

Description

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.

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CVSS v3.1 Score

4.5

MEDIUM

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

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

References

Other References

https://access.redhat.com/security/cve/CVE-2025-4877 https://bugzilla.redhat.com/show_bug.cgi?id=2376193 https://git.libssh.org/projects/libssh.git/commit/?h=stable-0.11&id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d https://www.libssh.org/security/advisories/CVE-2025-4877.txt

Frequently Asked Questions

What is CVE-2025-4877? +

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. It has a CVSS v3.1 base score of 4.5 (MEDIUM).

How severe is CVE-2025-4877? +

CVE-2025-4877 has a CVSS v3.1 score of 4.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2025-4877? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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