Stale pointer access in Linux kernel cpuset v2 mode check
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel cpuset controller reads a cgroup root pointer that can be stale while a new cgroup filesystem is being rebound, creating a potential use-after-free. The fix adds a cpuset_v2_mode flag, set when the cpuset_v2_mode mount option is used, so the check no longer reads that pointer.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: Don't access cpuset_cgrp_subsys.root in is_in_v2_mode() After seeing the patch [1] to guard is_in_v2_mode() with RCU, it makes me realize that is_in_v2_mode() may be called in a context where a new cgroup filesystem is being rebound with stale cpuset_cgrp_subsys.root pointer. Avoid this potential UaF situation by adding a new cpuset_v2_mode flag which is set when the cpuset_v2_mode mount option is used. This flag is written into only when cpuset_bind() is being called with a stable cpuset_cgrp_subsys.root value. The is_in_v2_mode() helper is modified to read the new cpuset_v2_mode flag instead of accessing cpuset_cgrp_subsys.root directly. [1] https://lore.kernel.org/lkml/[email protected]
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Upgrade the Linux kernel to 7.2.11 or 7.3. Red Hat Enterprise Linux 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 are listed as affected with no fix plan available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 7.2.11, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-23 Threatist record created from CVE-2026-98972
- 2026-10-23 Alias added: GHSA-pv9v-q67q-mhqc
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-29 CVSS score added · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
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Sources
- CVE-2026-98972 · CVE Program
- CVE-2026-98972 · NVD
- FIRST EPSS
- GHSA-pv9v-q67q-mhqc · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98972 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences