{"id":"CVE-2026-102916","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-102916","generatedAt":"2026-10-28T03:39:27.168Z","title":"A reachable assertion in the illumos bhyve instruction emulator allows a guest to panic the host.","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.","published":"2026-10-09T15:17:07.000Z","lastModified":"2026-10-09T22:16:55.000Z","status":"Awaiting Analysis","sourceIdentifier":"0ca53633-f0b5-4853-ba72-e0a2e62000d0","cvss":{"version":"4.0","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/M"},"cwe":["CWE-617"],"affected":[],"epss":{"score":0.00123,"percentile":0.02079,"date":"2026-10-27","history":[{"date":"2026-10-10","score":0.00123,"percentile":0.01881}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.12%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-09T15:17:07.000Z","detail":{"score":"6.8","severity":"MEDIUM","publishedAt":"2026-10-09T15:17:06.560Z"},"summary":"New CVE, medium severity (CVSS 6.8)."}],"references":[{"url":"https://github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae","source":"0ca53633-f0b5-4853-ba72-e0a2e62000d0"},{"url":"https://illumos.org/issues/18491","source":"0ca53633-f0b5-4853-ba72-e0a2e62000d0"},{"url":"https://illumos.topicbox.com/groups/developer/T697a32b688807e56/cve-2026-102916-18491-bhyve-rep-prefix-instr-emulation-fumbles-flags","source":"0ca53633-f0b5-4853-ba72-e0a2e62000d0"},{"url":"http://www.openwall.com/lists/oss-security/2026/10/09/19","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-102916","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}