CVE-2025-5987

Publication date 25 June 2025

Last updated 9 January 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

8.1 · High

Score breakdown

Description

A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error returned by the OpenSSL library. This issue can lead to undefined behavior, including compromised data confidentiality and integrity or crashes.

Status

Package Ubuntu Release Status
libssh 25.04 plucky
Fixed 0.11.1-1ubuntu0.1
24.10 oracular
Fixed 0.10.6-3ubuntu1.1
24.04 LTS noble
Fixed 0.10.6-2ubuntu0.1
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
libssh

Severity score breakdown

Parameter Value
Base score 8.1 · High
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

Other references