CVE-2026-1979
mruby JMPNOT-to-JMPIF Optimization vm.c mrb_vm_exec use after free
LOW 1.9EPSS 0.2%
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.
- Affected
- mruby
- CVSS v4.0 VULDB
- 1.9 LOW
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS v3.1 NVD
- 5.5 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS v3.1 VULDB
- 5.3 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L - CVSS v2.0 VULDB
- 4.3 MEDIUM
AV:L/AC:L/Au:S/C:P/I:P/A:P - EPSS
- 0.18% chance of exploitation in the next 30 days, 7th percentile
- Published
- 2026-02-06
- Updated
- 2026-02-23
Proof-of-concept exploits (1)
- mruby/mruby/issues/6701#issue-38026098435617★ · 2026-10-14
Security advisories
- https://vuldb.com/?id.344501
- https://vuldb.com/?submit.743377
- sysfce2/mruby/commit/e50f15c1c6e131fa7934355eb02b8173b13df415
- mruby/mruby/issues/6701