{"schemaVersion":3,"id":"CVE-2026-102916","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"A reachable assertion in the illumos bhyve instruction emulator allows a guest to panic the host. When emulating a REP-prefixed MOVS or STOS instruction that accesses guest MMIO, vie_emulate_movs() and vie_emulate_stos() in usr/src/uts/intel/io/vmm/vmm_instruction_emul.c do not clear the VIES_REPEAT status flag on the final iteration. For MMIO regions emulated in the kernel (the local APIC, I/O APIC and HPET), the stale flag causes a VERIFY assertion in vie_advance_pc() to fail, and the host panics. A privileged user within a guest VM can issue a REP MOVS or REP STOS instruction against the local APIC page to cause a denial of service of the host and every other guest running on it. The flaw has existed since 2020 (illumos-gate commit e0c0d44e), and affects any illumos distribution prior to illumos-gate commit 696ecf8d.","dates":{"published":"2026-10-09T14:12:08.832Z","modified":"2026-10-09T21:07:26.509Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.8,"severity":"medium","version":"4.0","versionLabel":"v4.0","source":"CVE.org","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:P/AU:Y/R:A/V:C","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":6.8,"severity":"medium","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:P/AU:Y/R:A/V:C","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":6.8,"severity":"medium","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:P/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:Y/R:A/V:C/RE:X/U:X","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00123,"percentile":0.019,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-10T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00123,"percentile":0.019}],"last30":[{"date":"2026-10-10T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00123,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00123,"percentile":0.019}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-617","name":"Reachable Assertion","description":"The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.","type":"weakness","status":"Draft","abstraction":"Base","likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/617.html"}],"affected":[{"vendor":"illumos","product":"illumos-gate","name":"illumos-gate","label":"illumos-gate","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ e0c0d44e917080841514d0dd031a696c74e8c435, < 696ecf8debceed9dc33937d8c8e111e4aeebfdae","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ e0c0d44e917080841514d0dd031a696c74e8c435, < 696ecf8debceed9dc33937d8c8e111e4aeebfdae","eol":null,"hubHref":"/vendor/illumos/illumos-gate"},{"vendor":"omnios","product":"omnios","name":"OmniOS","label":"omnios","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ any, < r151054","noFixRecorded":false,"fixedIn":null},{"text":"≥ r151058, < r151058w","noFixRecorded":false,"fixedIn":null},{"text":"≥ r151056, < r151056aw","noFixRecorded":false,"fixedIn":null},{"text":"≥ r151054, < r151054bw","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ any, < r151054 | ≥ r151058, < r151058w | ≥ r151056, < r151056aw | ≥ r151054, < r151054bw","eol":null,"hubHref":"/vendor/omnios/omnios"}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://illumos.topicbox.com/groups/developer/T697a32b688807e56/cve-2026-102916-18491-bhyve-rep-prefix-instr-emulation-fumbles-flags","label":"illumos.topicbox.com/groups/…","hostname":"illumos.topicbox.com","tags":["Mailing List"]},{"url":"https://illumos.org/issues/18491","label":"illumos.org/issues/18491","hostname":"illumos.org","tags":["Issue Tracking"]},{"url":"https://github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae","label":"github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae","hostname":"github.com","tags":["Patch"]},{"url":"http://www.openwall.com/lists/oss-security/2026/10/09/19","label":"www.openwall.com/lists/oss-security/2026/10/09/19","hostname":"www.openwall.com","tags":[]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-09T14:12:08.832Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-09T21:07:26.509Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":27,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T07:03:32.321Z","stale":false,"partial":false}}