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CVE-2026-81627VulnerabilityPublished Updated

QEMU. The VAPIC setup hypercall

Affects qemuSource GCVE Database

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Authoritative record:CVE-2026-81627· High 8.2

Not known to be exploited · CVSS 8.2 High.

Data as of 8 Nov 2026, 23:24 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (redhat)CVSS 3.18.2
EPSS
0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10qemupkg:deb/ubuntu/qemu?arch=source&distro=stonkingOther threatsAffected
  • 1:10.2.1+ds-1ubuntu3 – 1:11.0.3+ds-2ubuntu2
4 affected builds
Fixed in–
Ubuntu 26.10qemu-hwepkg:deb/ubuntu/qemu-hwe?arch=source&distro=stonkingOther threatsAffected
  • 1:10.2.1+ds-1ubuntu4 – 1:11.0.3+ds-2ubuntu4
5 affected builds
Fixed in–
Ubuntu 26.04 LTSqemupkg:deb/ubuntu/qemu?arch=source&distro=resoluteOther threatsAffected
  • 1:10.1.0+ds-5ubuntu2 – 1:10.2.1+ds-1ubuntu3.3
10 affected builds
Fixed in–
Ubuntu 26.04 LTSqemu-hwepkg:deb/ubuntu/qemu-hwe?arch=source&distro=resoluteOther threatsAffected
  • 1:10.2.1+ds-1ubuntu2 – 1:10.2.1+ds-1ubuntu4.4
5 affected builds
Fixed in–
Ubuntu 24.04 LTSqemupkg:deb/ubuntu/qemu?arch=source&distro=nobleOther threatsAffected
  • 1:8.0.4+dfsg-1ubuntu3 – 1:8.2.2+ds-0ubuntu1.18
24 affected builds
Fixed in–
Ubuntu 22.04 LTSqemupkg:deb/ubuntu/qemu?arch=source&distro=jammyOther threatsAffected
  • 1:6.0+dfsg-2expubuntu1 – 1:6.2+dfsg-2ubuntu6.31
35 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available via configuration changes. The VAPIC TPR optimization can be disabled by preventing the kvmvapic option ROM from loading. For libvirt-managed guests, add the following to the domain XML: <features><apic/><hyperv><vapic state='off'/></hyperv></features>. For direct QEMU usage, pass the command line option '-global kvmvapic.rom=off'. This mitigation disables the vulnerable optimization and is effective for 32-bit Windows guests using MMIO-based TPR register access. Linux guests, 64-bit Windows guests, and guests using x2APIC or MSR-based TPR access are unaffected by disabling this feature.

Description

A vulnerability in QEMU's VAPIC setup hypercall allows a privileged guest user on Q35/KVM machines to bypass chipset D_LCK protection by positioning a writable RAM alias over locked SMRAM, enabling code injection into System Management Mode memory. This flaw affects specific Ubuntu package versions of QEMU. Exploitation requires guest root access and KVM acceleration. Mitigation involves disabling the VAPIC TPR optimization by preventing the kvmvapic option ROM from loading. This issue primarily impacts 32-bit Windows guests using MMIO-based TPR register access; other guests are unaffected by the mitigation.

References

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