# CVE-2026-102916: illumos bhyve instruction emulator assertion denial of service

Source: https://junglewise.ai/threats/cve-2026-102916-a-reachable-assertion-in-the-illumos-bhyve-instruction-emulator  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-09. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-102916 · Severity: info · Published 2026-10-09

The bhyve virtual machine hypervisor in illumos fails to properly handle repeated memory instructions (MOVS and STOS) that access memory-mapped hardware regions. A user with access to a guest virtual machine can trigger a crash in the host hypervisor, causing a denial of service affecting the host and all other guest VMs running on it.

Technologies: [Illumos](https://junglewise.ai/threats/technologies/illumos). Vendors: [Illumos](https://junglewise.ai/threats/vendors/illumos).

## Quick answers

**Is CVE-2026-102916 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-102916 being exploited in the wild.

**How severe is CVE-2026-102916?** Informational severity, published 9 October 2026.

**Which products and versions are affected?** Illumos prior to commit 696ecf8d; affected since 2020 (commit e0c0d44e).

**Is there a fix for CVE-2026-102916?** Yes: fixed in illumos-gate commit 696ecf8d. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-102916 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-102916?** Check whether you run Illumos at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in illumos-gate commit 696ecf8d

## Technical details

A reachable assertion vulnerability exists in the instruction emulation code (vie_emulate_movs and vie_emulate_stos functions) where the VIES_REPEAT status flag is not cleared after the final iteration of REP-prefixed instructions that access MMIO regions. This causes a VERIFY assertion failure in vie_advance_pc(), leading to host panic. The vulnerability requires privilege within a guest VM and can be triggered by issuing a REP MOVS or REP STOS instruction targeting the local APIC page.

## Affected products

- illumos illumos prior to commit 696ecf8d; affected since 2020 (commit e0c0d44e)

## Timeline

- 2026-10-09: disclosed

## References

- [https://illumos.org/](https://illumos.org/)
- [https://github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae](https://github.com/illumos/illumos-gate/commit/696ecf8debceed9dc33937d8c8e111e4aeebfdae)

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- [illumos nscd unbounded file descriptor allocation](https://junglewise.ai/threats/cve-2026-104112-a-missing-release-of-resources-in-the-illumos-name-service-cache)