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CVE-2026-102916

MEDIUMCVSS 6.8/10

Last modified

CVE-2026-102916 is a medium-severity vulnerability rated 6.8/10 on the CVSS scale. 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.

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.

Metrics

CVSS 4.0
6.8/10

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

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
illumosillumos-gate>= e0c0d44e917080841514d0dd031a696c74e8c435, < 696ecf8debceed9dc33937d8c8e111e4aeebfdae
OmniOSOmniOS>= any, < r151054; >= r151058, < r151058w; >= r151056, < r151056aw; >= r151054, < r151054bw

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-102916?
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.
How severe is CVE-2026-102916?
CVE-2026-102916 has a CVSS score of 6.8/10 (MEDIUM severity).
How do I fix CVE-2026-102916?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST