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TI-2026-01636 Aliases CVE-2026-1979GHSA-gxgq-rpmr-r8xr

mruby JMPNOT-to-JMPIF Optimization vm.c mrb_vm_exec use after free

Priority MEDIUM 55CWE-119Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
Low · Low · Low
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00183 7th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD and the CNA
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
—mruby3.0; 3.1; 3.2; 3.3; 3.4.0—No fix listedCNA
  • mruby Vendor— Affected 3.0; 3.1; 3.2; 3.3; 3.4.0 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mruby:mruby:*:*:*:*:*:ruby:*:*up to 3.4.0Vulnerablemruby
  • cpe:2.3:a:mruby:mruby:*:*:*:*:*:ruby:*:* Versions up to 3.4.0 Vulnerable ·mruby

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-1979
  2. 2026-10-03 Alias added: GHSA-gxgq-rpmr-r8xr

References

Exploit 2

Patch 1

Other 1

  • TI-2022-00033 Heap-based Buffer Overflow in mruby/mruby CVSS 3.1CRITICAL 9.8
  • TI-2025-11794 mruby array.c ary_fill_exec out-of-bounds write CVSS 4.0MEDIUM 4.8
  • TI-2025-06567 mruby nregs codegen.c scope_new heap-based overflow CVSS 4.0MEDIUM 4.8
  • TI-2018-07224 In versions of mruby up to and including 1.4.0, an integer overflow exists in… CVSS 3.1CRITICAL 9.8
  • TI-2022-01100 Use-After-Free in str_escape in mruby/mruby in mruby/mruby CVSS 3.1CRITICAL 9.8
  • TI-2020-12486 mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class… CVSS 3.1CRITICAL 9.8
See all 41 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences