# CVE-2025-4877

## Summary

- **CVE ID:** CVE-2025-4877
- **Severity:** MEDIUM
- **CVSS Score:** 4.5 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L)
- **CWE:** CWE-787
- **Published:** Aug 20, 2025
- **Last Modified:** Aug 31, 2026

## 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.

## Affected Products

- Unknown product (0)
- Red Hat — Red Hat Enterprise Linux 9 (0:0.10.4-18.el9)

## References

- [CNA](https://access.redhat.com/security/cve/CVE-2025-4877)
- [CNA](https://bugzilla.redhat.com/show_bug.cgi?id=2376193)
- [CNA](https://git.libssh.org/projects/libssh.git/commit/?h=stable-0.11&id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d)
- [CNA](https://www.libssh.org/security/advisories/CVE-2025-4877.txt)
- [CNA](https://access.redhat.com/errata/RHSA-2026:18683)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.20%
- **EPSS Percentile:** 9.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._