{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-39953 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-39953 is a medium-severity denial of service vulnerability in Linux kernel, published on 4 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-39953 and fix it if it is affected.\n\nWhat it is: CVE-2025-39953 is a medium-severity denial of service vulnerability in Linux kernel, published on 4 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-39953 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-39953/ (Markdown: https://insights.sbomify.com/CVE-2025-39953/index.md)","id":"CVE-2025-39953","markdown":"https://insights.sbomify.com/CVE-2025-39953/index.md","name":"CVE-2025-39953","record":{"aliases":["AZL-68165","AZL-75179","BELL-CVE-2025-39953","DEBIAN-CVE-2025-39953","GHSA-vgcj-37hg-gm6g","ROOT-OS-DEBIAN-11-CVE-2025-39953","ROOT-OS-DEBIAN-12-CVE-2025-39953","ROOT-OS-DEBIAN-13-CVE-2025-39953","ROOT-OS-UBUNTU-2204-CVE-2025-39953","ROOT-OS-UBUNTU-2404-CVE-2025-39953","UBUNTU-CVE-2025-39953"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A race condition in Linux kernel cgroup workqueues can cause a system hang during controller mount/unmount operations, leading to denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup: split cgroup_destroy_wq into 3 workqueues\n\nA hung task can occur during [1] LTP cgroup testing when repeatedly\nmounting/unmounting perf_event and net_prio controllers with\nsystemd.unified_cgroup_hierarchy=1. The hang manifests in\ncgroup_lock_and_drain_offline() during root destruction.\n\nRelated case:\ncgroup_fj_function_perf_event cgroup_fj_function.sh perf_event\ncgroup_fj_function_net_prio cgroup_fj_function.sh net_prio\n\nCall Trace:\n\tcgroup_lock_and_drain_offline+0x14c/0x1e8\n\tcgroup_destroy_root+0x3c/0x2c0\n\tcss_free_rwork_fn+0x248/0x338\n\tprocess_one_work+0x16c/0x3b8\n\tworker_thread+0x22c/0x3b0\n\tkthread+0xec/0x100\n\tret_from_fork+0x10/0x20\n\nRoot Cause:\n\nCPU0                            CPU1\nmount perf_event                umount net_prio\ncgroup1_get_tree                cgroup_kill_sb\nrebind_subsystems               // root destruction enqueues\n\t\t\t\t// cgroup_destroy_wq\n// kill all perf_event css\n                                // one perf_event css A is dying\n                                // css A offline enqueues cgroup_destroy_wq\n                                // root destruction will be executed first\n                                css_free_rwork_fn\n                                cgroup_destroy_root\n                                cgroup_lock_and_drain_offline\n                                // some perf descendants are dying\n                                // cgroup_destroy_wq max_active = 1\n                                // waiting for css A to die\n\nProblem scenario:\n1. CPU0 mounts perf_event (rebind_subsystems)\n2. CPU1 unmounts net_prio (cgroup_kill_sb), queuing root destruction work\n3. A dying perf_event CSS gets queued for offline after root destruction\n4. Root destruction waits for offline completion, but offline work is\n   blocked behind root destruction in cgroup_destroy_wq (max_active=1)\n\nSolution:\nSplit cgroup_destroy_wq into three dedicated workqueues:\ncgroup_offline_wq – Handles CSS offline operations\ncgroup_release_wq – Manages resource release\ncgroup_free_wq – Performs final memory deallocation\n\nThis separation eliminates blocking in the CSS free path while waiting for\noffline operations to complete.\n\n[1] https://github.com/linux-test-project/ltp/blob/master/runtest/controllers","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"cgroup: split cgroup_destroy_wq into 3 workqueues","id":"CVE-2025-39953","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2025"},"n_packages":0,"n_references":8,"next":{"headline":"clk: sunxi-ng: mp: Fix dual-divider clock rate readback","id":"CVE-2025-39954"},"packages":[],"prev":{"headline":"wifi: wilc1000: avoid buffer overflow in WID string configuration","id":"CVE-2025-39952"},"products":["Linux"],"published":"2025-10-04","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-15","vendors":["Linux"]},"summary":"A race condition in Linux kernel cgroup workqueues can cause a system hang during controller mount/unmount operations, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2025-39953/"}