SB2026090557 - Race condition in Linux kernel hv driver

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-80895)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 0 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause use of partially initialized virtual processor fields.

The vulnerability exists due to improper synchronization in the MSHV pt_vp_array publication path when an irqfd fast-path assertion races concurrent virtual processor creation. A local user can register an irqfd targeting an as-yet-uncreated virtual processor and trigger the fast path concurrently with its creation to cause use of partially initialized virtual processor fields.

The condition can occur on weakly ordered architectures, where a non-NULL array pointer may become visible before virtual processor initialization stores.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/062aa5dcc49a9ad96726a80c2a0ab0a1233bc2b9
• https://git.kernel.org/stable/c/b098dc869219c15dc49bf9cf63fb5fc1481d3373
• https://git.kernel.org/stable/c/eba2bf5daa7933f94c53ebbbf0f567d4274716df