CVE-2026-81627: Qemu-kvm: vapic writable rom alias can escape the option-rom window and expose locked smram
Vulnerability summary
CVE-2026-81627 is a high (CVSS 8.2) Out-of-bounds Write vulnerability in qemu. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.8% of scored vulnerabilities.
Not severe (CVSS 8.2, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 4 · Related 4Timeline
- 18-09-2026PublishedVulnerability first disclosed.
- 30-10-2026Last modifiedVulnerability information updated.
Description
A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management Mode memory.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated8.2HighCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.2HighCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- NVDNIST8.2HighCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS trend
Probability
0.19%
Chance of exploitation in the next 30 days
Percentile
9%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.19% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu2 products
- qemuAll versions (No fix recorded)
- qemu-hweAll versions (No fix recorded)
Debian1 product
- qemuAll versions (No fix recorded) | < 1:11.1.2+ds-1
2 vendors · 3 products
