VulnerabilityDeferred

CVE-2025-58151

The exact vulnerable behaviour depends on the code generated by the compiler.

CRITICAL 9.4EPSS 0.14%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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 4.0: 9.4 CRITICALCVSS: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/M
EPSS: 0.14% probability · 3th percentile
CISA KEV: Not listed
Weakness: CWE-367
Source: security@xen.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.