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CVE-2025-58151

38
FAUCET Score

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.

First published: Jul 9, 2026Last modified: Jul 9, 2026

Impacted Technologies

VendorProductVersion(s)CPE
XenVarstored
allCNA affecteddefault unaffected

CVSS Data

CVSS version used by this source: 4.0

9.4CRITICAL

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

Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
HIGH
SS Confidentiality
HIGH
SS Integrity
HIGH
SS Availability
HIGH
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.12%
Probability of exploitation in next 30 days
EPSS Percentile
2.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0012 is in the 3rd percentile among its peer group of 79 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.7 Bluesky, 0.3 Mastodon, and 1.0 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

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