Improper Check for Unusual or Exceptional Conditions in Linux kernel - CVE-2026-98542

Vulnerability details

The vulnerability allows a local privileged user to bypass cpuset CPU exclusivity constraints and create partitions with overlapping exclusive CPU assignments.

The vulnerability exists due to improper handling of conflicting CPU assignments in remote_partition_enable() in kernel/cgroup/cpuset.c when enabling a remote partition beneath an existing local partition through a non-partition intermediate cgroup. A local privileged user can configure a remote partition to claim CPUs already owned by the ancestor local partition because the conflict check emits a warning but allows partition creation to proceed.

Affected software

How to mitigate CVE-2026-98542

External References

• https://git.kernel.org/stable/c/0751ab665cb3dcdac224b002565f2e28461740d5
• https://git.kernel.org/stable/c/241e67b60308cdce25bba66616a109759edd1d40
• https://git.kernel.org/stable/c/31c88350b7dd1522792f726f79607f31bb55c50f

Related Security Bulletins

• Improper Check for Unusual or Exceptional Conditions in Linux kernel selftests cgroup
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more