CVE-2026-1979

MEDIUM

mruby <3.4.0 - Use After Free

Title source: llm
STIX 2.1

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.

References (7)

Core 7
Core References
Various Sources product
https://github.com/mruby/mruby/
Permissions Required, VDB Entry vdb-entry technical-description
https://vuldb.com/?id.344501
Permissions Required, VDB Entry signature permissions-required
https://vuldb.com/?ctiid.344501
Permissions Required, VDB Entry third-party-advisory
https://vuldb.com/?submit.743377
Issue Tracking issue-tracking
https://github.com/mruby/mruby/issues/6701
Issue Tracking exploit issue-tracking
https://github.com/mruby/mruby/issues/6701#issue-3802609843

Scores

CVSS v3 5.3
EPSS 0.0003
EPSS Percentile 7.5%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-119 CWE-416
Status published
Products (1)
mruby/mruby < 3.4.0
Published Feb 06, 2026
Tracked Since Feb 18, 2026