TI-2026-59222 Aliases CVE-2026-86547 GHSA-42q4-rvcw-q7wc

mrubyc through 4.0.0 NULL Pointer Dereference via OP_ENTER

LOW 30CWE-476Published 2026-09-09 · Updated 2026-09-09

Key facts

Attack vector: Local
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-476.

Summary

mrubyc through 4.0.0 contains a null pointer dereference vulnerability in the op_enter() handler in src/vm.c when processing untrusted bytecode. Attackers can craft malicious .mrb bytecode files with OP_ENTER instructions at the top level to crash the embedding application and cause denial of service.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00184 8th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
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

Vendor	Product	Affected versions	Fixed in	Status	Source
mrubyc	mrubyc	2.0 – 4.0.0	—	No fix listed	CNA

mrubyc Vendormrubyc Affected 2.0 – 4.0.0 Fixed in — No fix listed CNA

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2026-86547
2026-10-03 Alias added: GHSA-42q4-rvcw-q7wc

References

Other 2

Sources

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