CVE-2026-1979

Name	CVE-2026-1979
Description	A flaw has been found in mruby up to 3.4.0. This affects the function mrb_vm_exec of the file src/vm.c of the component JMPNOT-to-JMPIF Optimization. Executing a manipulation can lead to use after free. The attack needs to be launched locally. The exploit has been published and may be used. This patch is called e50f15c1c6e131fa7934355eb02b8173b13df415. It is advisable to implement a patch to correct this issue.
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	1127317

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
mruby (PTS)	bullseye	2.1.2-3	vulnerable
	bookworm	3.1.0-3	vulnerable
	trixie	3.3.0-1	vulnerable
	forky, sid	3.4.0-2	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
mruby	source	(unstable)	(unfixed)			1127317

Notes

[trixie] - mruby <no-dsa> (Minor issue)
[bookworm] - mruby <no-dsa> (Minor issue)
https://github.com/mruby/mruby/issues/6701
https://github.com/sysfce2/mruby/commit/e50f15c1c6e131fa7934355eb02b8173b13df415