CVE-2025-58151

UNKNOWN 0.0

varstored: TOCTOU issues with mapped guest memory

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-367
Vendor	xen
Product	varstored
Published	Jul 9, 2026
Last Updated	Jul 9, 2026

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Affected Versions

Xen / varstored

all

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

This issue was discovered by Teddy Astie of Vates.