CVE-2026-86547

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.

Scoring

Severity
MEDIUM
CVSS base score
6.9
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CWE
CWE-476
Published
2026-09-09
Last modified
2026-09-09

Affected products

Weakness type

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