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Review reviewHigh

CVE-2026-53264

Linux Linux, linux kernel

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() <-- holds the idr lock 0: rcu_read_lock() 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR) 0: mutex_unlock() <-- releases the idr lock 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) <-- Action remov...

CVSS
7.8
EPSS
0.20%
10.3% percentile
CISA KEV
Not listed
Published
2026.06.25
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.20%
Technical severityCVSS 7.8

Vulnerability overview

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() <-- holds the idr lock 0: rcu_read_lock() 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR) 0: mutex_unlock() <-- releases the idr lock 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) <-- Action remov...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 98b2e40879abf0245be5a5b7af69e0f6ff524ac3, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 18af5d2ef0c4f65787fd1280c8b23286b9f2a835, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 1f1b98fea6b9ea30507d0f2fbff6750292d097e2, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 8b136f18ac4b2ace5aaad3305b3f8a5d8165a009, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 5dd51e09020c65aa53cf128e5e3517cd53b3c113, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < b60e9391142e983fab2be53497aa8f71fdd09cd5, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 91d105d2cbe002f9c7b43a6183adedc37e1da1f7, >= d7fb60b9cafb982cb2e46a267646a8dfd4f2e5da < 5057e1aca011e51ef51498c940ef96f3d3e8a305, >= 4.14, >= 4.14 < 5.10.259, >= 5.11 < 5.15.210, >= 5.16 < 6.1.176, >= 6.2 < 6.6.143, >= 6.7 < 6.12.94, >= 6.13 < 6.18.36, >= 6.19 < 7.0.13, 7.1
Fixed versions
5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416