CVE-2025-21634

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-01-19. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

cgroup/cpuset: remove kernfs active break

A warning was found:

WARNING: CPU: 10 PID: 3486953 at fs/kernfs/file.c:828 CPU: 10 PID: 3486953 Comm: rmdir Kdump: loaded Tainted: G RIP: 0010:kernfs_should_drain_open_files+0x1a1/0x1b0 RSP: 0018:ffff8881107ef9e0 EFLAGS: 00010202 RAX: 0000000080000002 RBX: ffff888154738c00 RCX: dffffc0000000000 RDX: 0000000000000007 RSI: 0000000000000004 RDI: ffff888154738c04 RBP: ffff888154738c04 R08: ffffffffaf27fa15 R09: ffffed102a8e7180 R10: ffff888154738c07 R11: 0000000000000000 R12: ffff888154738c08 R13: ffff888750f8c000 R14: ffff888750f8c0e8 R15: ffff888154738ca0 FS: 00007f84cd0be740(0000) GS:ffff8887ddc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555f9fbe00c8 CR3: 0000000153eec001 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kernfs_drain+0x15e/0x2f0 __kernfs_remove+0x165/0x300 kernfs_remove_by_name_ns+0x7b/0xc0 cgroup_rm_file+0x154/0x1c0 cgroup_addrm_files+0x1c2/0x1f0 css_clear_dir+0x77/0x110 kill_css+0x4c/0x1b0 cgroup_destroy_locked+0x194/0x380 cgroup_rmdir+0x2a/0x140

It can be explained by: rmdir echo 1 > cpuset.cpus kernfs_fop_write_iter // active=0 cgroup_rm_file kernfs_remove_by_name_ns kernfs_get_active // active=1 __kernfs_remove // active=0x80000002 kernfs_drain cpuset_write_resmask wait_event //waiting (active == 0x80000001) kernfs_break_active_protection // active = 0x80000001 // continue kernfs_unbreak_active_protection // active = 0x80000002 ... kernfs_should_drain_open_files // warning occurs kernfs_put_active

This warning is caused by 'kernfs_break_active_protection' when it is writing to cpuset.cpus, and the cgroup is removed concurrently.

The commit 3a5a6d0c2b03 ("cpuset: don't nest cgroup_mutex inside get_online_cpus()") made cpuset_hotplug_workfn asynchronous, This change involves calling flush_work(), which can create a multiple processes circular locking dependency that involve cgroup_mutex, potentially leading to a deadlock. To avoid deadlock. the commit 76bb5ab8f6e3 ("cpuset: break kernfs active protection in cpuset_write_resmask()") added 'kernfs_break_active_protection' in the cpuset_write_resmask. This could lead to this warning.

After the commit 2125c0034c5d ("cgroup/cpuset: Make cpuset hotplug processing synchronous"), the cpuset_write_resmask no longer needs to wait the hotplug to finish, which means that concurrent hotplug and cpuset operations are no longer possible. Therefore, the deadlock doesn't exist anymore and it does not have to 'break active protection' now. To fix this warning, just remove kernfs_break_active_protection operation in the 'cpuset_write_resmask'.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
3.6%
KEV
Not listed

Published

January 19, 2025

Last Modified

October 1, 2025

References (2)

Patch Availability(17)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-lowlatency-64k (6.11.0-1011.12) @ oracular2026-05-30ubuntu
ubuntulinux-tools-lowlatency-hwe-24.04-edge (6.11.0-1011.12~24.04.1) @ noble2026-05-30ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.11.0-21.21) @ oracular2026-05-30ubuntu
ubuntulinux-tools-gke (6.8.0-1025.29) @ noble2026-05-30ubuntu
ubuntulinux-tools-oem-24.04a (6.8.0-1028.28) @ noble2026-05-30ubuntu
ubuntulinux-tools-raspi (6.11.0-1010.10) @ oracular2026-05-30ubuntu
ubuntulinux-tools-oem-24.04b (6.11.0-1017.17) @ noble2026-05-30ubuntu
ubuntulinux-tools-realtime (6.8.1-1022.23) @ noble2026-05-30ubuntu
ubuntulinux-virtual (6.8.0-60.63) @ noble2026-05-30ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k (6.8.0-1028.31.1) @ noble2026-05-30ubuntu
ubuntulinux-tools-azure-nvidia (6.8.0-1016.17) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-edge (6.8.0-1026.27~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-raspi (6.8.0-1028.32) @ noble2026-05-30ubuntu
ubuntulinux-tools-gkeop-6.8 (6.8.0-1012.14) @ noble2026-05-30ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-60.63~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-raspi-realtime (6.8.0-2023.24) @ noble2026-05-30ubuntu
linuxKernel @ 6.12.10—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(16)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 13× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-24 17:41 UTCOSV refresh
  2. 2026-07-24 14:17 UTCEPSS rescore
  3. 2026-07-23 14:17 UTCEPSS rescore
  4. 2026-07-23 02:50 UTCEG score recompute
  5. 2026-07-22 14:07 UTCEPSS rescore
  6. 2026-07-22 14:07 UTCEPSS rescore
  7. 2026-07-21 15:24 UTCEPSS rescore
  8. 2026-07-20 17:07 UTCEPSS rescore
  9. 2026-07-19 14:30 UTCEPSS rescore
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  11. 2026-07-19 02:28 UTCEPSS rescore
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  13. 2026-07-18 10:03 UTCEPSS rescore
  14. 2026-07-16 17:02 UTCEPSS rescore
  15. 2026-07-15 16:57 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 01:59 UTCEPSS rescore
  18. 2026-07-13 22:29 UTCEPSS rescore
  19. 2026-07-13 22:29 UTCEPSS rescore
  20. 2026-07-13 06:12 UTCEPSS rescore
  21. 2026-07-13 06:12 UTCEPSS rescore
  22. 2026-07-12 05:46 UTCEPSS rescore
  23. 2026-07-12 05:46 UTCEPSS rescore
  24. 2026-07-11 08:27 UTCEPSS rescore
  25. 2026-07-11 08:26 UTCEPSS rescore
Show 69 more
  1. 2026-07-09 19:09 UTCEPSS rescore
  2. 2026-07-08 15:14 UTCEPSS rescore
  3. 2026-07-07 13:45 UTCEPSS rescore
  4. 2026-07-07 12:51 UTCOSV refresh
  5. 2026-07-06 16:26 UTCEPSS rescore
  6. 2026-07-06 02:22 UTCEPSS rescore
  7. 2026-07-06 02:22 UTCEPSS rescore
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 06:30 UTCEPSS rescore
  10. 2026-07-01 15:06 UTCEPSS rescore
  11. 2026-06-30 23:21 UTCEPSS rescore
  12. 2026-06-30 23:21 UTCEPSS rescore
  13. 2026-06-29 14:06 UTCEPSS rescore
  14. 2026-06-28 14:07 UTCEPSS rescore
  15. 2026-06-28 14:07 UTCEPSS rescore
  16. 2026-06-28 04:55 UTCEPSS rescore
  17. 2026-06-28 04:55 UTCEPSS rescore
  18. 2026-06-27 03:08 UTCEPSS rescore
  19. 2026-06-27 03:08 UTCEPSS rescore
  20. 2026-06-25 13:49 UTCEPSS rescore
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-24 14:04 UTCEPSS rescore
  23. 2026-06-24 14:04 UTCEPSS rescore
  24. 2026-06-23 21:32 UTCEPSS rescore
  25. 2026-06-23 21:32 UTCEPSS rescore
  26. 2026-06-22 14:25 UTCEPSS rescore
  27. 2026-06-22 14:25 UTCEPSS rescore
  28. 2026-06-21 14:56 UTCEPSS rescore
  29. 2026-06-21 14:56 UTCEPSS rescore
  30. 2026-06-21 01:59 UTCEPSS rescore
  31. 2026-06-21 01:59 UTCEPSS rescore
  32. 2026-06-19 19:25 UTCEPSS rescore
  33. 2026-06-19 19:25 UTCEPSS rescore
  34. 2026-06-19 00:05 UTCOSV refresh
  35. 2026-06-18 17:52 UTCEPSS rescore
  36. 2026-06-18 17:52 UTCEPSS rescore
  37. 2026-06-17 17:52 UTCEPSS rescore
  38. 2026-06-16 17:52 UTCEPSS rescore
  39. 2026-06-16 17:52 UTCEPSS rescore
  40. 2026-06-15 17:48 UTCEPSS rescore
  41. 2026-06-14 23:17 UTCEPSS rescore
  42. 2026-06-13 22:59 UTCEPSS rescore
  43. 2026-06-12 23:11 UTCEPSS rescore
  44. 2026-06-11 13:59 UTCEPSS rescore
  45. 2026-06-10 22:18 UTCEPSS rescore
  46. 2026-06-10 13:22 UTCEPSS rescore
  47. 2026-06-08 14:16 UTCEPSS rescore
  48. 2026-06-08 14:16 UTCEPSS rescore
  49. 2026-06-07 15:24 UTCEPSS rescore
  50. 2026-06-07 15:24 UTCEPSS rescore
  51. 2026-06-06 13:47 UTCEPSS rescore
  52. 2026-06-06 13:47 UTCEPSS rescore
  53. 2026-06-05 22:46 UTCEPSS rescore
  54. 2026-06-05 22:46 UTCEPSS rescore
  55. 2026-06-04 13:11 UTCEPSS rescore
  56. 2026-06-04 13:11 UTCEPSS rescore
  57. 2026-06-02 20:12 UTCEPSS rescore
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  59. 2026-06-01 13:51 UTCEPSS rescore
  60. 2026-06-01 13:51 UTCEPSS rescore
  61. 2026-05-31 22:30 UTCEPSS rescore
  62. 2026-05-31 22:30 UTCEPSS rescore
  63. 2026-05-31 00:16 UTCEPSS rescore
  64. 2026-05-31 00:16 UTCEPSS rescore
  65. 2026-05-30 13:06 UTCEG score recompute
  66. 2026-05-30 13:06 UTCVendor advisory
  67. 2026-05-30 13:06 UTCGHSA enrichment
  68. 2026-05-30 07:20 UTCOSV refresh
  69. 2026-05-29 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-21634?
CVE-2025-21634 is a medium vulnerability published on January 19, 2025. In the Linux kernel, the following vulnerability has been resolved: cgroup/cpuset: remove kernfs active break A warning was found: WARNING: CPU: 10 PID: 3486953 at fs/kernfs/file.c:828 CPU: 10 PID: 3486953 Comm: rmdir Kdump: loaded Tainted: G RIP: 0010:kernfsshoulddrainopenfiles+0x1a1/0x1b0 RSP:…
When was CVE-2025-21634 disclosed?
CVE-2025-21634 was first published in the National Vulnerability Database on January 19, 2025, with the most recent update on October 1, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21634 actively exploited?
CVE-2025-21634 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2025-21634?
CVE-2025-21634 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21634?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21634, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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