{"id":"CVE-2026-86547","aliases":["EUVD-2026-74787","GHSA-42q4-rvcw-q7wc"],"status":"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.","severity":{"version":"4.0","score":6.9,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00184,"percentile":0.08043,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":false},"cwes":["CWE-476"],"published":"2026-09-09T10:07:25Z","modified":"2026-10-28T02:30:33Z","exploits":[{"source":"pocgithub","id":"HarshRajSinghania/cve-2026-86547-mrubyc-op-enter","title":"HarshRajSinghania/cve-2026-86547-mrubyc-op-enter","date":"2026-09-12","url":"https://github.com/HarshRajSinghania/cve-2026-86547-mrubyc-op-enter"}],"products":[{"vendor":"mrubyc","product":"mrubyc"}],"references":[{"url":"https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537","tags":["technical-description","article"]},{"url":"https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1534","tags":["technical-description","article"]},{"url":"https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-enter","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86547","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-42q4-rvcw-q7wc"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86547.json","tags":["advisory"]},{"url":"https://github.com/mrubyc/mrubyc","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-86547","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.","status":"published","published":"2026-09-09T10:07:25.743Z","modified":"2026-09-09T12:41:16.443Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium","assessor":"cna"},{"version":"3.1","score":6.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T13:49:42.666099Z"}],"euvd":[{"id":"EUVD-2026-74787","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.","status":"published","published":"2026-09-09T10:07:25Z","modified":"2026-09-09T12:41:16Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"updated_at":"2026-11-02T17:28:27.763941Z"}],"ghsa":[{"id":"GHSA-42q4-rvcw-q7wc","title":"mrubyc through 4.0.0 contains a null pointer dereference vulnerability in the op_enter() handler...","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.","status":"published","published":"2026-09-09T12:32:11Z","modified":"2026-09-09T12:32:11Z","cvss":[{"version":"4.0","score":6.9,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"},{"version":"3.1","score":6.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T15:11:38.096751Z"}],"nvd":[{"id":"CVE-2026-86547","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.","status":"published","published":"2026-09-09T10:22:33.803Z","modified":"2026-09-10T19:58:20.507Z","cvss":[{"version":"4.0","score":6.9,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T14:12:45.93749Z"}],"osv":[{"id":"CVE-2026-86547","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.","status":"published","published":"2026-09-09T10:07:25.743Z","modified":"2026-10-28T02:30:33.804314069Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"cwes":["CWE-476"],"updated_at":"2026-11-02T15:45:18.825071Z"}]}}