CVE-2025-39953cgroup: split cgroup_destroy_wq into 3 workqueues
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: cgroup: split cgroup_destroy_wq into 3 workqueues A hung task can occur during [1] LTP cgroup testing when repeatedly mounting/unmounting perf_event and net_prio controllers with systemd.unified_cgroup_hierarchy=1. The hang manifests in cgroup_lock_and_drain_offline() during root destruction. Related case: cgroup_fj_function_perf_event cgroup_fj_function.sh perf_event cgroup_fj_function_net_prio cgroup_fj_function.sh net_prio Call Trace: cgroup_lock_and_drain_offline+0x14c/0x1e8 cgroup_destroy_root+0x3c/0x2c0 css_free_rwork_fn+0x248/0x338 process_one_work+0x16c/0x3b8 worker_thread+0x22c/0x3b0 kthread+0xec/0x100 ret_from_fork+0x10/0x20 Root Cause: CPU0 CPU1 mount perf_event umount net_prio cgroup1_get_tree cgroup_kill_sb rebind_subsystems // root destruction enqueues // cgroup_destroy_wq // kill all perf_event css // one perf_event css A is dying // css A offline enqueues cgroup_destroy_wq // root destruction will be executed first css_free_rwork_fn cgroup_destroy_root cgroup_lock_and_drain_offline // some perf descendants are dying // cgroup_destroy_wq max_active = 1 // waiting for css A to die Problem scenario: 1. CPU0 mounts perf_event (rebind_subsystems) 2. CPU1 unmounts net_prio (cgroup_kill_sb), queuing root destruction work 3. A dying perf_event CSS gets queued for offline after root destruction 4. Root destruction waits for offline completion, but offline work is blocked behind root destruction in cgroup_destroy_wq (max_active=1) Solution: Split cgroup_destroy_wq into three dedicated workqueues: cgroup_offline_wq – Handles CSS offline operations cgroup_release_wq – Manages resource release cgroup_free_wq – Performs final memory deallocation This separation eliminates blocking in the CSS free path while waiting for offline operations to complete. [1] https://github.com/linux-test-project/ltp/blob/master/runtest/controllers
- CVSS
- 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from 334c3679ec4b2b113c35ebe37d2018b112dd5013 before cabadd7fd15f97090f752fd22dd7f876a0dc3dc4; from 334c3679ec4b2b113c35ebe37d2018b112dd5013 before a0c896bda7077aa5005473e2c5b3c27173313b4c; from 334c3679ec4b2b113c35ebe37d2018b112dd5013 before f2795d1b92506e3adf52a298f7181032a1525e04; from 334c3679ec4b2b113c35ebe37d2018b112dd5013 before 993049c9b1355c78918344a6403427d53f9ee700; 334c3679ec4b2b113c35ebe37d2018b112dd5013 builds before 4a1e3ec28e8062cd9f339aa6a942df9c5bcb6811; from 334c3679ec4b2b113c35ebe37d2018b112dd5013 before ded4d207a3209a834b6831ceec7f39b934c74802; 334c3679ec4b2b113c35ebe37d2018b112dd5013 builds before 05e0b03447cf215ec384210441b34b7a3b16e8b0; 334c3679ec4b2b113c35ebe37d2018b112dd5013 builds before 79f919a89c9d06816dbdbbd168fa41d27411a7f9 | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 4.6 before 5.4.300; from 5.5 before 5.10.245; from 5.11 before 5.15.194; from 5.16 before 6.1.154; from 6.2 before 6.6.108; from 6.7 before 6.12.49; from 6.13 before 6.16.9; 6.17; and 5 more ranges | NVD |
References
- https://git.kernel.org/stable/c/cabadd7fd15f97090f752fd22dd7f876a0dc3dc4patch
- https://git.kernel.org/stable/c/a0c896bda7077aa5005473e2c5b3c27173313b4cpatch
- https://git.kernel.org/stable/c/f2795d1b92506e3adf52a298f7181032a1525e04patch
- https://git.kernel.org/stable/c/993049c9b1355c78918344a6403427d53f9ee700patch
- https://git.kernel.org/stable/c/4a1e3ec28e8062cd9f339aa6a942df9c5bcb6811patch
- https://git.kernel.org/stable/c/ded4d207a3209a834b6831ceec7f39b934c74802patch
- https://git.kernel.org/stable/c/05e0b03447cf215ec384210441b34b7a3b16e8b0patch
- https://git.kernel.org/stable/c/79f919a89c9d06816dbdbbd168fa41d27411a7f9patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.