CVE-2026-18839

Name	CVE-2026-18839
Description	An integer underflow was found in the popt library when formatting help text for option tables that exceed the terminal width. A local user who can cause an application to print help under those conditions may cause that application to crash or fail to display help, resulting in a denial of service of the affected application.
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
popt (PTS)	bullseye	1.18-2	vulnerable
	bookworm	1.19+dfsg-1	vulnerable
	forky, sid, trixie	1.19+dfsg-2	vulnerable

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

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

https://bugzilla.redhat.com/show_bug.cgi?id=2511010