CVE-2026-86547CWE-476

CVE-2026-86547

Medium · published September 9, 2026

CVSS v3.1
6.2
EPSS
0%
Percentile
7.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.2 · MEDIUM
Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
6.9 · 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
EPSS
0.00184 · 7.5th percentile
Weakness
CWE-476 · NULL Pointer Dereference
Published
2026-09-09T14:22Z
References (3)
https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1534 · [email protected]https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537 · [email protected]https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-enter · [email protected]
EPSS history
Timeline
  • 11 SEP 03:19Z
    EPSS moved — → 0%
    epss
  • 09 SEP 10:07Z
    mrubyc through 4.0.0 NULL Pointer Dereference via OP_ENTER
    cvelistv5