CVE-2026-3731

Name	CVE-2026-3731
Description	A weakness has been identified in libssh up to 0.11.3. The impacted element is the function sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may be performed from remote. Upgrading to version 0.11.4 and 0.12.0 is sufficient to resolve this issue. This patch is called 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60. You should upgrade the affected component.
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	1127693

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libssh (PTS)	bullseye	0.9.8-0+deb11u1	vulnerable
	bullseye (security)	0.9.8-0+deb11u2	vulnerable
	bookworm	0.10.6-0+deb12u2	vulnerable
	bookworm (security)	0.10.6-0+deb12u1	vulnerable
	trixie	0.11.2-1+deb13u1	vulnerable
	forky, sid	0.11.3-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libssh	source	(unstable)	(unfixed)			1127693

Notes

[trixie] - libssh <no-dsa> (Minor issue)
[bookworm] - libssh <no-dsa> (Minor issue)
https://www.libssh.org/security/advisories/libssh-2026-sftp-extensions.txt
Fixed by: https://git.libssh.org/projects/libssh.git/commit/?id=f80670a7aba86cbb442c9b115c9eaf4ca04601b8 (libssh-0.11.4)
Testcase: https://git.libssh.org/projects/libssh.git/commit/?id=02c6f5f7ec8629a7cff6a28cde9701ab10304540 (libssh-0.11.4)