CVE-2026-86547
mediummrubyc through 4.0.0 contains a null pointer dereference vulnerability in the op_enter() handler in src/vm.c when processing untrusted bytecode.
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.
CVSS
6.2
6.2 (CVSS v3.1)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Severity source: NVD CVSS v3.1 (disclosure@vulncheck.com)
Timeline (UTC)
Published: 2026-09-09 10:22
Modified: 2026-09-10 19:58
NVD status: Deferred
Last synced 1 day ago
Verified against the source API 2026-10-27 06:52 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1... disclosure@vulncheck.com
- https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537 disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-... disclosure@vulncheck.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:52 UTC · record ↗