SB20260816441 - Use-after-free in Linux kernel xen driver



SB20260816441 - Use-after-free in Linux kernel xen driver

Published: August 16, 2026

Security Bulletin ID SB20260816441
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use-after-free (CVE-ID: CVE-2026-72085)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to a refcount underflow leading to use-after-free in xen-scsiback request handling when processing pvSCSI requests before command submission. A remote user can submit requests with a bad grant reference or an unknown request type to cause a denial of service.

Under panic_on_warn, triggering the refcount underflow can panic the host. The issue can also leak every command tag of a LUN session, stopping the LUN.


Remediation

Install update from vendor's website.