Improper access control in Linux kernel - CVE-2026-80921
Published: September 9, 2026
Vulnerability identifier: #VU148747
CSH Severity: Low
CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-80921
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to access a device that is no longer available.
The vulnerability exists due to improper access control in KVM s390 VSIE APCB shadowing when shadowing crypto access bits from a format 0 APCB. A local user can use stale crypto access bits to access a device that is no longer available.
The issue affects nested guest environments.
Affected software
Linux kernel
How to mitigate CVE-2026-80921
Install security update from vendor's repository.
External References
- https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733
- https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6
- https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b
- https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d
- https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf
- https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d
- https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f
- https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b
- https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f