CVE-2026-6390

Name	CVE-2026-6390
Description	A flaw was found in GNU nano's multi-buffer error message handling. When a user opens multiple files at startup and one triggers an ALERT-level error, a specially crafted filename containing printf format specifiers can be reinterpreted. This format string vulnerability may allow an attacker to achieve stack information disclosure, cause a denial of service (crash), or potentially perform arbitrary memory writes.
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)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
nano (PTS)	bullseye	5.4-2+deb11u3	vulnerable
	bookworm	7.2-1+deb12u1	vulnerable
	trixie	8.4-1+deb13u1	vulnerable
	forky	9.1-1	fixed
	sid	9.2-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
nano	source	(unstable)	9.0-1

Notes

[trixie] - nano <no-dsa> (Minor issue)
[bookworm] - nano <postponed> (Minor issue)
[bullseye] - nano <postponed> (Minor issue)
https://bugzilla.redhat.com/show_bug.cgi?id=2458767
https://cgit.git.savannah.gnu.org/cgit/nano.git/commit/?id=0b7328bce452bf1b0bbff81276425d4809a9b6fd (v9.0)