{"id":"CVE-2026-86547","title":"mrubyc through 4.0.0 contains a null pointer dereference vulnerability in the op_enter() handler in src/vm.c when processing untrusted bytecode","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 leve…","severity":"medium","cvss":6.2,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-476"],"vendor":"mrubyc","product":"mrubyc","affected":["mrubyc >= 2.0 <= 4.0.0"],"published":"2026-09-09","updated":"2026-09-10","sourceUpdated":"2026-09-10T19:58:20.507","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-86547","references":[{"url":"https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1534","label":"disclosure@vulncheck.com"},{"url":"https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-enter","label":"disclosure@vulncheck.com"}],"tags":["nvd","cve.org","exploit-available"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-09T12:41:01.119978Z"},"ingestedAt":"2026-09-10T14:24:27.789Z","epss":0.00129,"epssPercentile":0.02899,"exploits":{"github":1,"githubRepos":["https://github.com/HarshRajSinghania/cve-2026-86547-mrubyc-op-enter"],"checkedAt":"2026-09-24T07:53:22.004Z"},"exploitAvailable":true,"slug":"CVE-2026-86547","body":"## Overview\n\nmrubyc 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":46,"depthScoreParts":{"impact":34.1,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[]}