CVE-2025-4877

Name	CVE-2025-4877
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, 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
	trixie	0.11.2-1	fixed
	forky, sid	0.11.3-1	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-2025-4877.txt
Fixed by: https://git.libssh.org/projects/libssh.git/commit/?id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d (libssh-0.11.2)