CVE-2026-86547
Medium
Description
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.
SeverityMedium
CVSS6.2
Exploit probability—
ProductMrubyc
PublishedSep 9, 2026
First seenSep 9, 2026
Weakness typeCWE-476NULL pointer dereference
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mrubyc mrubyc | 2.0 ≤ v ≤ 4.0.0 | — |
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