CVE-2026-98542
Microsoft — cgroup/cpuset: Return PERR_NOCPUS in remote_partition_enable() on subpartitions_cpus conflict
Microsoft · Not classified by connected sources
EVRS 0 of 100 Informational
Monitor
Rank 2,857 of 2,960 tracked
Why it scores 0
Evidence available: 2 of 8 signalsNo strong exploitation, disclosure, or severity signal is available for this CVE yet.
- CISA KEVDid not apply
- RansomwareNo data
- Vendor exploitationNo data
- EPSSDid not apply
- Microsoft Exploitability IndexNo data
- Pre-patch disclosureNo data
- KEV recencyNo data
- CVSSNo data
The band answers “how soon”, not “how bad”. No data for: Ransomware, Vendor exploitation, Microsoft Exploitability Index, Pre-patch disclosure, KEV recency, CVSS. Why some signals show no data
Fix
No fixed version identified yetAffected versions
Not identified by the connected sources
Remediation
NVD lists one or more references for this CVE that aren't tagged as a patch or vendor advisory. Review them directly to confirm patch availability and applicability before making a remediation decision.
Evidence
Each value with its source| Measure | Value | Source |
|---|---|---|
| CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. | Not publishedNVD and the CVE record were checked and hold no score. | NVD |
| FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. | 0.002 (9th pctl) | FIRST EPSS |
| Actively exploitedWhether a source of record has confirmed attacks using it in the wild. | Not confirmed | Patch Tuesday |
| Public exploit moduleA module existing is not the same as active exploitation. | None known | Metasploit |
| EUVD cross-referenceENISA's record: CVSS 0.0, assigned by Linux. | Listed | ENISA EUVD |
Description
NVDIn the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: Return PERR_NOCPUS in remote_partition_enable() on subpartitions_cpus conflict When a remote partition is created underneath an existing local partition via a non-partition (PRS_MEMBER) intermediate cgroup, update_prstate() sees parent->partition_root_state == PRS_MEMBER and calls remote_partition_enable(). Commit 86888c7bd117 ("cgroup/cpuset: Add warnings to catch inconsistency in exclusive CPUs") replaced the cpumask_intersects(tmp->new_cpus, subpartitions_cpus) error check in remote_partition_enable() with WARN_ON_ONCE(). As a result, remote_partition_enable() emits a warning and proceeds to enable the remote partition on CPUs that are already owned by the ancestor local partition in subpartitions_cpus. This can be reproduced on Linux 7.3.0-rc3 with: mkdir -p /tmp/cg1 mount -t cgroup2 none /tmp/cg1 echo "+cpuset" > /tmp/cg1/cgroup.subtree_control mkdir /tmp/cg1/A echo 1 > /tmp/cg1/A/cpuset.cpus echo 1 > /tmp/cg1/A/cpuset.cpus.exclusive echo root > /tmp/cg1/A/cpuset.cpus.partition echo "+cpuset" > /tmp/cg1/A/cgroup.subtree_control mkdir /tmp/cg1/A/B echo 1 > /tmp/cg1/A/B/cpuset.cpus echo 1 > /tmp/cg1/A/B/cpuset.cpus.exclusive echo "+cpuset" > /tmp/cg1/A/B/cgroup.subtree_control mkdir /tmp/cg1/A/B/D echo 1 > /tmp/cg1/A/B/D/cpuset.cpus echo 1 > /tmp/cg1/A/B/D/cpuset.cpus.exclusive echo root > /tmp/cg1/A/B/D/cpuset.cpus.partition which triggers: WARNING: kernel/cgroup/cpuset.c:1594 at remote_partition_enable+0x1c1/0x300 and leaves both /tmp/cg1/A and /tmp/cg1/A/B/D as active root partitions claiming exclusive CPU 1. Fix this by returning PERR_NOCPUS when tmp->new_cpus intersects subpartitions_cpus in remote_partition_enable(), matching the error code used by remote_cpus_update() for the same subpartitions_cpus conflict, and add a regression test case to tools/testing/selftests/cgroup/test_cpuset_prs.sh. Tested in QEMU on Linux 7.3.0-rc3 using the reproducer above and tools/testing/selftests/cgroup/test_cpuset_prs.sh.