Critical 9.4Published Jul 9, 2026

CVE-2025-58151varstored is a component of the Xapi toolstack handling UEFI Variables for a VM.

Updated under an hour ago (2026-10-19 08:50 UTC)

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Exploited in the last 30 days

varstored is a component of the Xapi toolstack handling UEFI Variables for a VM. It has a communication path with OVMF inside the VM involving mapping a buffer prepared by OVMF. Within varstored, there were insufficient compiler barriers, creating TOCTOU issues with data in the shared buffer. The exact vulnerable behaviour depends on the code generated by the compiler. In a build of varstored using default settings, the attacker can control an index used in a jump table.

CVSS: 9.4 CRITICAL (v4.0, NVD)CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness (CWE): CWE-367
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Deferred
Record last updated: Sep 29, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

No affected products are listed yet.

References

https://xenbits.xen.org/xsa/advisory-478.html
http://www.openwall.com/lists/oss-security/2026/01/27/2
http://xenbits.xen.org/xsa/advisory-478.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.