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Advisory severityHigh7.0Red Hat Linux

High [CVE-2026-53264] use RCU with deferred freeing for action lifecycle

This high-severity Red Hat Linux advisory covers CVE-2026-53264 affecting Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions, Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-53264 Source published Source updated

VulniPulse record published Record updated

CVE-2026-53264
Affected products & platforms
Red Hat LinuxLinux Kernel
Open source advisory

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: use RCU with deferred freeing for action lifecycle When NEWTFILTER and DELFILTER are run concurrently it is possible to create a race with an associated action.

Let's illustrate with CPU0 running NEWTFILTER and CPU1 running DELFILTER: 0: mutex_lock() 0, mutex held 1: idr_remove(idr, index) tcfa_refcnt) 0, mutex held 1: idr_remove(idr, index) 1: mutex_unlock() 1: call_rcu(&p->tcfa_rcu, tcf_action_rcu_free) tcfa_refcnt) <-- fails, refcnt already 0 1: rcu_read_unlock() <-- release so freeing can run after grace period After CPU1 calls idr_remove(), the object is no longer reachable through the IDR.

CPU0's subsequent idr_find() will return NULL, and even if it still held a stale pointer, the immediate kfree()…

Affected products named by the advisory: Red Hat Enterprise Linux 10.0 Extended Update Support; Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions; Red Hat Enterprise Linux 9.6 Extended Update Support; and 2 more.

Affected products named by the advisory: Red Hat Enterprise Linux 8; Red Hat package: kernel-rt.

Is CVE-2026-53264 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53264 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-53264?

Upgrade to a fixed release named by Red Hat:

  • kernel-0:6.12.0-211.47.1.el10_2
  • kpatch-patch
  • kernel-0:6.12.0-55.98.1.el10_0
  • kernel-0:5.14.0-687.39.1.el9_8
  • kernel-0:5.14.0-284.187.1.el9_2
  • kernel-rt-0:5.14.0-284.187.1.rt14.472.el9_2
  • kernel-0:5.14.0-427.144.1.el9_4
  • kernel-0:5.14.0-570.134.1.el9_6
  • RHSA-2026:54343
  • RHSA-2026:62642
  • RHSA-2026:55445
  • RHSA-2026:54443

8 more fixed releases are listed below.

Confirm against the vendor advisory before you patch.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 14 days ago·verify at source

Fixed versions
  • kernel-0:6.12.0-211.47.1.el10_2
  • kpatch-patch
  • kernel-0:6.12.0-55.98.1.el10_0
  • kernel-0:5.14.0-687.39.1.el9_8
  • kernel-0:5.14.0-284.187.1.el9_2
  • kernel-rt-0:5.14.0-284.187.1.rt14.472.el9_2
  • kernel-0:5.14.0-427.144.1.el9_4
  • kernel-0:5.14.0-570.134.1.el9_6
  • RHSA-2026:54343
  • RHSA-2026:62642
  • RHSA-2026:55445
  • RHSA-2026:54443
  • RHSA-2026:62640
  • RHSA-2026:54515
  • RHSA-2026:55443
  • RHSA-2026:62638
  • RHSA-2026:54482
  • RHSA-2026:62639
  • RHSA-2026:53990
  • RHSA-2026:62641

Official advisory · high-confidence parse· fetched 14 days ago·verify at source

Mitigation

Upgrade to a fixed release: kernel-0:6.12.0-211.47.1.el10_2, kpatch-patch, kernel-0:6.12.0-55.98.1.el10_0, kernel-0:5.14.0-687.39.1.el9_8, kernel-0:5.14.0-284.187.1.el9_2, kernel-rt-0:5.14.0-284.187.1.rt14.472.el9_2. That is the remediation for this advisory.

The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.

Official advisory · high-confidence parse· fetched 14 days ago·verify at source

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