CVE-2025-21771

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-02-27. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
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:

sched_ext: Fix incorrect autogroup migration detection

scx_move_task() is called from sched_move_task() and tells the BPF scheduler that cgroup migration is being committed. sched_move_task() is used by both cgroup and autogroup migrations and scx_move_task() tried to filter out autogroup migrations by testing the destination cgroup and PF_EXITING but this is not enough. In fact, without explicitly tagging the thread which is doing the cgroup migration, there is no good way to tell apart scx_move_task() invocations for racing migration to the root cgroup and an autogroup migration.

This led to scx_move_task() incorrectly ignoring a migration from non-root cgroup to an autogroup of the root cgroup triggering the following warning:

WARNING: CPU: 7 PID: 1 at kernel/sched/ext.c:3725 scx_cgroup_can_attach+0x196/0x340 ... Call Trace: cgroup_migrate_execute+0x5b1/0x700 cgroup_attach_task+0x296/0x400 __cgroup_procs_write+0x128/0x140 cgroup_procs_write+0x17/0x30 kernfs_fop_write_iter+0x141/0x1f0 vfs_write+0x31d/0x4a0 __x64_sys_write+0x72/0xf0 do_syscall_64+0x82/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fix it by adding an argument to sched_move_task() that indicates whether the moving is for a cgroup or autogroup migration. After the change, scx_move_task() is called only for cgroup migrations and renamed to scx_cgroup_move_task().

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
—
EPSS
9.2%
KEV
Not listed

Published

February 27, 2025

Last Modified

October 28, 2025

References (3)

Vendor Advisories for CVE-2025-21771(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-0:6.12.0-124.8.1.el10_12025-11-11redhat

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.

Data Freshness Timeline

(refreshed 10× in last 7d / 44× 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. 2026-07-22 14:07 UTCEPSS rescore
  2. 2026-07-22 14:07 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-20 17:07 UTCEPSS rescore
  5. 2026-07-19 14:30 UTCEPSS rescore
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  7. 2026-07-19 02:28 UTCEPSS rescore
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  9. 2026-07-18 10:03 UTCEPSS rescore
  10. 2026-07-16 17:02 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 16:57 UTCEPSS rescore
  13. 2026-07-15 01:59 UTCEPSS rescore
  14. 2026-07-13 22:29 UTCEPSS rescore
  15. 2026-07-13 22:29 UTCEPSS rescore
  16. 2026-07-13 06:12 UTCEPSS rescore
  17. 2026-07-13 06:12 UTCEPSS rescore
  18. 2026-07-12 05:46 UTCEPSS rescore
  19. 2026-07-12 05:46 UTCEPSS rescore
  20. 2026-07-11 08:27 UTCEPSS rescore
  21. 2026-07-11 08:26 UTCEPSS rescore
  22. 2026-07-09 19:09 UTCEPSS rescore
  23. 2026-07-08 15:14 UTCEPSS rescore
  24. 2026-07-07 13:45 UTCEPSS rescore
  25. 2026-07-07 09:21 UTCOSV refresh
Show 63 more
  1. 2026-07-06 16:26 UTCEPSS rescore
  2. 2026-07-06 02:22 UTCEPSS rescore
  3. 2026-07-06 02:22 UTCEPSS rescore
  4. 2026-07-05 02:30 UTCEPSS rescore
  5. 2026-07-04 06:30 UTCEPSS rescore
  6. 2026-07-01 15:06 UTCEPSS rescore
  7. 2026-06-29 14:06 UTCEPSS rescore
  8. 2026-06-28 14:07 UTCEPSS rescore
  9. 2026-06-28 14:07 UTCEPSS rescore
  10. 2026-06-28 04:55 UTCEPSS rescore
  11. 2026-06-28 04:55 UTCEPSS rescore
  12. 2026-06-27 03:08 UTCEPSS rescore
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  14. 2026-06-25 13:49 UTCEPSS rescore
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  16. 2026-06-24 14:04 UTCEPSS rescore
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  18. 2026-06-23 21:32 UTCEPSS rescore
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  20. 2026-06-22 14:25 UTCEPSS rescore
  21. 2026-06-22 14:25 UTCEPSS rescore
  22. 2026-06-21 14:56 UTCEPSS rescore
  23. 2026-06-21 14:56 UTCEPSS rescore
  24. 2026-06-21 01:59 UTCEPSS rescore
  25. 2026-06-21 01:59 UTCEPSS rescore
  26. 2026-06-19 19:25 UTCEPSS rescore
  27. 2026-06-19 19:25 UTCEPSS rescore
  28. 2026-06-18 20:13 UTCOSV refresh
  29. 2026-06-18 17:52 UTCEPSS rescore
  30. 2026-06-18 17:52 UTCEPSS rescore
  31. 2026-06-17 17:52 UTCEPSS rescore
  32. 2026-06-16 17:52 UTCEPSS rescore
  33. 2026-06-16 17:52 UTCEPSS rescore
  34. 2026-06-15 17:48 UTCEPSS rescore
  35. 2026-06-14 23:17 UTCEPSS rescore
  36. 2026-06-13 22:59 UTCEPSS rescore
  37. 2026-06-12 23:11 UTCEPSS rescore
  38. 2026-06-11 13:59 UTCEPSS rescore
  39. 2026-06-10 22:18 UTCEPSS rescore
  40. 2026-06-10 13:22 UTCEPSS rescore
  41. 2026-06-08 14:16 UTCEPSS rescore
  42. 2026-06-08 14:16 UTCEPSS rescore
  43. 2026-06-06 13:47 UTCEPSS rescore
  44. 2026-06-06 13:47 UTCEPSS rescore
  45. 2026-06-05 22:46 UTCEPSS rescore
  46. 2026-06-05 22:46 UTCEPSS rescore
  47. 2026-06-05 06:10 UTCEPSS rescore
  48. 2026-06-05 06:10 UTCEPSS rescore
  49. 2026-06-04 13:11 UTCEPSS rescore
  50. 2026-06-04 13:11 UTCEPSS rescore
  51. 2026-06-02 20:12 UTCEPSS rescore
  52. 2026-06-02 20:12 UTCEPSS rescore
  53. 2026-06-01 13:51 UTCEPSS rescore
  54. 2026-06-01 13:51 UTCEPSS rescore
  55. 2026-05-31 22:30 UTCEPSS rescore
  56. 2026-05-31 22:30 UTCEPSS rescore
  57. 2026-05-31 00:16 UTCEPSS rescore
  58. 2026-05-31 00:16 UTCEPSS rescore
  59. 2026-05-30 10:32 UTCEG score recompute
  60. 2026-05-30 10:32 UTCVendor advisory
  61. 2026-05-30 10:32 UTCGHSA enrichment
  62. 2026-05-29 17:20 UTCOSV refresh
  63. 2026-05-29 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-21771?
CVE-2025-21771 is a medium vulnerability published on February 27, 2025. In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix incorrect autogroup migration detection scxmovetask() is called from schedmovetask() and tells the BPF scheduler that cgroup migration is being committed. schedmovetask() is used by both cgroup and autogroup…
When was CVE-2025-21771 disclosed?
CVE-2025-21771 was first published in the National Vulnerability Database on February 27, 2025, with the most recent update on October 28, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21771 actively exploited?
CVE-2025-21771 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 9.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2025-21771?
CVE-2025-21771 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21771?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21771, 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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