SB2026091738 - Use of Uninitialized Variable in Linux kernel s390 kvm
Published: September 17, 2026
Security Bulletin ID
SB2026091738
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Information disclosure
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use of Uninitialized Variable (CVE-ID: CVE-2026-89921)
CWE-ID: CWE-457 - Use of Uninitialized Variable
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to use of uninitialized stack data structures in __kvm_inject_pfault_token() when using migration ioctls after page-fault token injection. A local user can retrieve stale stack values to disclose sensitive information.
The stale values are not exposed to the guest through interrupt delivery.
Remediation
Install update from vendor's website.