CVE-2025-58151 — varstored: TOCTOU issues with mapped guest memory

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
Xen / varstored	affected all

CWE

CWE-367

References

https://xenbits.xen.org/xsa/advisory-478.html

ADP enrichment

CVE

No English description supplied.

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

CISA-ADP

No English description supplied.

No references supplied.