CVE-2025-5987

Name	CVE-2025-5987
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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1108407

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libssh (PTS)	bullseye (security), bullseye	0.9.8-0+deb11u1	vulnerable
	bookworm, bookworm (security)	0.10.6-0+deb12u1	vulnerable
	sid, trixie	0.11.2-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libssh	source	(unstable)	0.11.2-1			1108407

Notes

[bookworm] - libssh <no-dsa> (Minor issue)
[bullseye] - libssh <postponed> (Minor issue)
https://www.libssh.org/security/advisories/CVE-2025-5987.txt
Fixed by: https://git.libssh.org/projects/libssh.git/commit/?id=90b4845e0c98574bbf7bea9e97796695f064bf57 (libssh-0.11.2)