{"id":"CVE-2026-86547","state":"PUBLISHED","title":"mrubyc through 4.0.0 NULL Pointer Dereference via OP_ENTER","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.","publishedAt":"2026-09-09T10:07:25.743Z","updatedAt":"2026-09-09T12:41:16.443Z","severity":{"score":6.9,"label":"Medium","version":"4.0","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","source":"VulnCheck"},"assigner":"VulnCheck","products":["mrubyc mrubyc"],"affected":[{"vendor":"mrubyc","product":"mrubyc","packageName":"mrubyc","packageURL":"pkg:github/mrubyc/mrubyc","defaultStatus":"unaffected","versions":[{"version":"2.0","status":"affected","lessThanOrEqual":"4.0.0","versionType":"custom"}],"collectionURL":"https://github.com/mrubyc/mrubyc","repo":"https://github.com/mrubyc/mrubyc"}],"references":["https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537","https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1534","https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-enter"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/86xxx/CVE-2026-86547.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-86547","state":"PUBLISHED","datePublished":"2026-09-09T10:07:25.743Z","dateUpdated":"2026-09-09T12:41:16.443Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-09-08T00:49:47.457Z"},"containers":{"cna":{"title":"mrubyc through 4.0.0 NULL Pointer Dereference via OP_ENTER","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"mrubyc","product":"mrubyc","packageName":"mrubyc","packageURL":"pkg:github/mrubyc/mrubyc","defaultStatus":"unaffected","versions":[{"version":"2.0","status":"affected","lessThanOrEqual":"4.0.0","versionType":"custom"}],"collectionURL":"https://github.com/mrubyc/mrubyc","repo":"https://github.com/mrubyc/mrubyc"}],"references":[{"url":"https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537","tags":["technical-description"]},{"url":"https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1534","tags":["technical-description"]},{"url":"https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-enter","name":"VulnCheck Advisory: mrubyc through 4.0.0 NULL Pointer Dereference via OP_ENTER","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","baseScore":6.2,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"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","attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","lang":"en","description":"NULL Pointer Dereference","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-09-09T10:07:25.743Z"},"datePublic":"2026-09-07T00:00:00.000Z","credits":[{"lang":"en","value":"Harsh Raj Singhania","type":"finder"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-09T12:41:01.119978Z","id":"CVE-2026-86547","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-09T12:41:16.443Z"}}]}}}