NULL pointer dereference in Linux kernel perf PMU scheduling
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: 4 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel perf subsystem passes a NULL context to the PMU sched_task callback, which causes a kernel NULL pointer dereference. The Arm armv8pmu_sched_task implementation crashes on this path only when BRBE is in use, a feature added in v6.17. Linux kernel versions from 6.2 are affected until the fixed releases listed below.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix NULL pmu_ctx passed to pmu->sched_task() perf_pmu_sched_task() returns early when cpuctx->task_ctx is set, and cpc->task_epc is only non-NULL while a task context is scheduled in on this CPU. __perf_pmu_sched_task() therefore always passes NULL: Unable to handle kernel NULL pointer dereference at virtual address 00 pc : armv8pmu_sched_task+0x14/0x50 Call trace: armv8pmu_sched_task+0x14/0x50 (P) perf_pmu_sched_task+0xac/0x108 __perf_event_task_sched_out+0x6c/0xe0 Pass &cpc->epc instead, the CPU-wide context for this PMU, which the function already dereferences a few lines up to find pmu. armv8pmu_sched_task() is the only in-tree implementation that dereferences the argument, and it only reads ->pmu, so the oops needs BRBE, added in v6.17.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to 6.6.160, 6.12.112, 6.18.55, 7.2.9 or 7.3. Red Hat lists Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 and Red Hat OpenShift Container Platform 5 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.112, 6.18.55, 7.2.9, 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 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: 5 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98477
- 2026-10-18 Alias added: GHSA-23r4-4gr3-gjfw
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@98181f9721f75f1a544dc563b0d8fed1d5c398d5 · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/98181f9721f75f1a544dc563b0d8fed1d5c398d5
- https://git.kernel.org/stable/c/b5409311b606d536cc485f3706c242c2afa93edb
- https://git.kernel.org/stable/c/249a2bd87a0e57dc28f36e992807edc9cae309b5
- https://git.kernel.org/stable/c/ec15f6a50183fc01f470af74ad49900fb3731fca
- https://git.kernel.org/stable/c/36bb85cf36cab15fb611cb44b78a5df06e4e69a2
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Sources
- CVE-2026-98477 · CVE Program
- CVE-2026-98477 · NVD
- FIRST EPSS
- GHSA-23r4-4gr3-gjfw · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98477 · Red Hat security data · CC BY 4.0
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