CVE-2025-39953 json
cgroup: split cgroup_destroy_wq into 3 workqueues
published 2025-10-04 13 mo ago modified 2026-10-19 20 d ago also EUVD-2025-32383
- cvss
- 5.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 4%
- public exploits
- 0
- none known
Summary
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
Patch / fix
- Linux Linux 5.4.300, 5.10.245, 5.15.194, 6.1.154, 6.6.108, 6.12.49, 6.16.9, 6.17
- linux Debian 12 6.1.158-1
- linux Debian 13 6.12.57-1
- linux Debian 14 6.16.9-1
debian advisories DEBIAN-CVE-2025-39953
- linux Ubuntu 22.04 LTS 5.15.0-170.180
- linux Ubuntu 24.04 LTS 6.8.0-106.106
- linux-aws Ubuntu 22.04 LTS 5.15.0-1100.107
- linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
- linux-gcp Ubuntu 22.04 LTS 5.15.0-1100.109
- linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
- linux-gke Ubuntu 22.04 LTS 5.15.0-1096.102
- linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53
ubuntu advisories UBUNTU-CVE-2025-39953
Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- kernel Azure Linux 3.0 6.6.112.1-1
- kernel CBL-Mariner 2.0 5.15.200.1-1
azure linux advisories AZL-68165AZL-75179
Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT
- git.kernel.org/stable/c/cabadd7fd15f97090f752fd22dd7f876a0dc3dc4 commit
- git.kernel.org/stable/c/a0c896bda7077aa5005473e2c5b3c27173313b4c commit
- git.kernel.org/stable/c/f2795d1b92506e3adf52a298f7181032a1525e04 commit
- git.kernel.org/stable/c/993049c9b1355c78918344a6403427d53f9ee700 commit
- git.kernel.org/stable/c/4a1e3ec28e8062cd9f339aa6a942df9c5bcb6811 commit
- git.kernel.org/stable/c/ded4d207a3209a834b6831ceec7f39b934c74802 commit
- git.kernel.org/stable/c/05e0b03447cf215ec384210441b34b7a3b16e8b0 commit
- git.kernel.org/stable/c/79f919a89c9d06816dbdbbd168fa41d27411a7f9 commit
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2025-39953 updated cvss 5.5
kernel: cgroup: split cgroup_destroy_wq into 3 workqueues
-
Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernelaffected: no fix available “Fix deferred”
-
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 morenot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
cisa ICSA-26-295-11 updated cvss 5.5
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP
-
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.7 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.7affected: mitigation, no fix available
Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf
cisa ICSA-26-209-04 updated cvss 5.5
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP
-
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.6 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.6affected: mitigation, no fix available
Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Affected products
- Linux Linux
- Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
- Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
- Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classification
- Technology feeds
References
-
git.kernel.org
/stable/c/cabadd7fd15f97090f752fd22dd7f876a0dc3dc4
patch
-
git.kernel.org
/stable/c/a0c896bda7077aa5005473e2c5b3c27173313b4c
patch
-
git.kernel.org
/stable/c/f2795d1b92506e3adf52a298f7181032a1525e04
patch
-
git.kernel.org
/stable/c/993049c9b1355c78918344a6403427d53f9ee700
patch
-
git.kernel.org
/stable/c/4a1e3ec28e8062cd9f339aa6a942df9c5bcb6811
patch
-
git.kernel.org
/stable/c/ded4d207a3209a834b6831ceec7f39b934c74802
patch
-
git.kernel.org
/stable/c/05e0b03447cf215ec384210441b34b7a3b16e8b0
patch
-
git.kernel.org
/stable/c/79f919a89c9d06816dbdbbd168fa41d27411a7f9
patch
- cert-portal.siemens.com /productcert/html/ssa-019113.html
- cert-portal.siemens.com /productcert/html/ssa-457936.html
Sources
- CVE List CVE-2025-39953
- NVD CVE-2025-39953
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.