CVE-2025-4877

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. Limited direct impact.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-08-20 13:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-05 16:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 4.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-08-20 13:15 UTC

Last modified

2026-11-05 16:17 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-787 · Out-of-bounds write

Record status

Deferred

Attack profile CVSS 3.1 · 4.5

Attack vector

Local

Complexity

High

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-4877.md and follow it. Check whether this project is affected by CVE-2025-4877. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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