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.

CVSS

No CVSS.

References

Link	Resource
https://github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae
https://illumos.org/issues/18491
https://illumos.topicbox.com/groups/developer/T697a32b688807e56/cve-2026-102916-18491-bhyve-rep-prefix-instr-emulation-fumbles-flags
http://www.openwall.com/lists/oss-security/2026/10/09/19

Configurations

No configuration.

History

09 Oct 2026, 22:16

Type	Values Removed	Values Added
References		() http://www.openwall.com/lists/oss-security/2026/10/09/19 -

09 Oct 2026, 15:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-09 15:17

Updated : 2026-10-09 22:16

NVD link : CVE-2026-102916

Mitre link : CVE-2026-102916

CVE.ORG link : CVE-2026-102916

JSON object : View

Products Affected

No product.

CWE

CWE-617

Reachable Assertion

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