CVE-2026-81627: Red Hat Enterprise Linux 10 · Out-of-bounds Write
Affects Red Hat Enterprise Linux 10Source CVE Database V5
Not known to be exploited · CVSS 8.2 High.
Data as of 2 Nov 2026, 11:12 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 8.2 |
|---|
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 2 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10qemu-kvm | Affected– | Fixed in– |
| Red Hat Enterprise Linux 6qemu-kvm | Affected– | Fixed in– |
| Red Hat Enterprise Linux 7qemu-kvm | Affected– | Fixed in– |
| Red Hat Enterprise Linux 7qemu-kvm-ma | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8virt-devel:rhel/qemu-kvm | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8virt:rhel/qemu-kvm | Affected– | Fixed in– |
AI-suggested
Red Hat advises disabling the VAPIC TPR optimization to mitigate this vulnerability. This can be done by preventing the kvmvapic option ROM from loading. For libvirt-managed guests, add the following to the guest's 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 affects only 32-bit Windows guests using MMIO-based TPR register access and does not impact Linux guests, 64-bit Windows guests, or guests using x2APIC or MSR-based TPR access.
Description
CVE-2026-81627 is a vulnerability in QEMU affecting Red Hat Enterprise Linux 10 where a privileged guest user on a Q35/KVM machine can exploit improper validation in the VAPIC setup hypercall to bypass chipset D_LCK protection and inject code into System Management Mode (SMM) memory. This flaw allows code injection into locked SMRAM by positioning a writable RAM alias outside the option ROM window. Exploitation requires guest root access and KVM acceleration. The vulnerability is rated high severity with a CVSS score of 8.2. Mitigation involves disabling the VAPIC TPR optimization by preventing the kvmvapic option ROM from loading, which affects only 32-bit Windows guests using MMIO-based TPR register access.