CVE-2025-21840

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-03-07. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header

The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY attribute to receive HFI events from kernel space, encounters a segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the commands and the events for the thresholds").

The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value was changed while intel_lpmd still uses the old value.

Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit itself is questionable.

The commit introduced a new element in the middle of enum thermal_genl_attr, which affects many existing attributes and introduces potential risks and unnecessary maintenance burdens for userspace thermal netlink event users.

Solve the issue by moving the newly introduced THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the enum thermal_genl_attr. This ensures that all existing thermal generic netlink attributes remain unaffected.

[ rjw: Subject edits ]

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
11%
KEV
Not listed

Published

March 7, 2025

Last Modified

October 29, 2025

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.13.4osv

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 7× in last 7d / 40× 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.

Showing the most recent 100 of 109 total refreshes for this CVE.

  1. 2026-08-07 16:26 UTCEPSS rescore
  2. 2026-08-06 13:46 UTCEPSS rescore
  3. 2026-08-05 19:16 UTCEPSS rescore
  4. 2026-08-04 15:09 UTCEPSS rescore
  5. 2026-08-04 10:37 UTCEPSS rescore
  6. 2026-08-03 10:35 UTCEPSS rescore
  7. 2026-08-02 02:25 UTCEPSS rescore
  8. 2026-08-01 04:15 UTCEPSS rescore
  9. 2026-07-30 16:27 UTCEPSS rescore
  10. 2026-07-30 01:29 UTCEPSS rescore
  11. 2026-07-28 15:35 UTCEPSS rescore
  12. 2026-07-27 14:12 UTCEPSS rescore
  13. 2026-07-26 14:53 UTCEPSS rescore
  14. 2026-07-25 14:17 UTCEPSS rescore
  15. 2026-07-24 14:17 UTCEPSS rescore
  16. 2026-07-24 12:41 UTCOSV refresh
  17. 2026-07-23 14:17 UTCEPSS rescore
  18. 2026-07-23 02:50 UTCEG score recompute
  19. 2026-07-22 14:07 UTCEPSS rescore
  20. 2026-07-22 14:07 UTCEPSS rescore
  21. 2026-07-21 15:24 UTCEPSS rescore
  22. 2026-07-20 17:07 UTCEPSS rescore
  23. 2026-07-19 14:30 UTCEPSS rescore
  24. 2026-07-19 14:30 UTCEPSS rescore
  25. 2026-07-19 02:28 UTCEPSS rescore
Show 75 more
  1. 2026-07-19 02:28 UTCEPSS rescore
  2. 2026-07-18 10:03 UTCEPSS rescore
  3. 2026-07-16 17:02 UTCEPSS rescore
  4. 2026-07-15 16:57 UTCEPSS rescore
  5. 2026-07-15 16:57 UTCEPSS rescore
  6. 2026-07-15 01:59 UTCEPSS rescore
  7. 2026-07-13 22:29 UTCEPSS rescore
  8. 2026-07-13 22:29 UTCEPSS rescore
  9. 2026-07-13 06:12 UTCEPSS rescore
  10. 2026-07-13 06:12 UTCEPSS rescore
  11. 2026-07-12 05:46 UTCEPSS rescore
  12. 2026-07-12 05:46 UTCEPSS rescore
  13. 2026-07-11 08:27 UTCEPSS rescore
  14. 2026-07-11 08:26 UTCEPSS rescore
  15. 2026-07-09 19:09 UTCEPSS rescore
  16. 2026-07-08 15:14 UTCEPSS rescore
  17. 2026-07-07 13:45 UTCEPSS rescore
  18. 2026-07-07 08:21 UTCOSV refresh
  19. 2026-07-06 16:26 UTCEPSS rescore
  20. 2026-07-06 02:22 UTCEPSS rescore
  21. 2026-07-06 02:22 UTCEPSS rescore
  22. 2026-07-05 02:30 UTCEPSS rescore
  23. 2026-07-04 06:30 UTCEPSS rescore
  24. 2026-07-01 15:06 UTCEPSS rescore
  25. 2026-06-30 23:21 UTCEPSS rescore
  26. 2026-06-30 23:21 UTCEPSS rescore
  27. 2026-06-29 14:06 UTCEPSS rescore
  28. 2026-06-28 14:07 UTCEPSS rescore
  29. 2026-06-28 14:07 UTCEPSS rescore
  30. 2026-06-28 04:55 UTCEPSS rescore
  31. 2026-06-28 04:55 UTCEPSS rescore
  32. 2026-06-27 03:08 UTCEPSS rescore
  33. 2026-06-27 03:08 UTCEPSS rescore
  34. 2026-06-25 13:49 UTCEPSS rescore
  35. 2026-06-25 13:49 UTCEPSS rescore
  36. 2026-06-24 14:04 UTCEPSS rescore
  37. 2026-06-24 14:04 UTCEPSS rescore
  38. 2026-06-23 21:32 UTCEPSS rescore
  39. 2026-06-23 21:32 UTCEPSS rescore
  40. 2026-06-22 14:25 UTCEPSS rescore
  41. 2026-06-22 14:25 UTCEPSS rescore
  42. 2026-06-21 14:56 UTCEPSS rescore
  43. 2026-06-21 14:56 UTCEPSS rescore
  44. 2026-06-21 01:59 UTCEPSS rescore
  45. 2026-06-21 01:59 UTCEPSS rescore
  46. 2026-06-19 19:25 UTCEPSS rescore
  47. 2026-06-19 19:25 UTCEPSS rescore
  48. 2026-06-18 19:13 UTCOSV refresh
  49. 2026-06-18 17:52 UTCEPSS rescore
  50. 2026-06-18 17:52 UTCEPSS rescore
  51. 2026-06-17 17:52 UTCEPSS rescore
  52. 2026-06-16 17:52 UTCEPSS rescore
  53. 2026-06-16 17:52 UTCEPSS rescore
  54. 2026-06-15 17:48 UTCEPSS rescore
  55. 2026-06-14 23:17 UTCEPSS rescore
  56. 2026-06-13 22:59 UTCEPSS rescore
  57. 2026-06-12 23:11 UTCEPSS rescore
  58. 2026-06-11 13:59 UTCEPSS rescore
  59. 2026-06-10 22:18 UTCEPSS rescore
  60. 2026-06-10 13:22 UTCEPSS rescore
  61. 2026-06-08 14:16 UTCEPSS rescore
  62. 2026-06-08 14:16 UTCEPSS rescore
  63. 2026-06-07 15:24 UTCEPSS rescore
  64. 2026-06-07 15:24 UTCEPSS rescore
  65. 2026-06-06 13:47 UTCEPSS rescore
  66. 2026-06-06 13:47 UTCEPSS rescore
  67. 2026-06-05 22:46 UTCEPSS rescore
  68. 2026-06-05 22:46 UTCEPSS rescore
  69. 2026-06-05 06:10 UTCEPSS rescore
  70. 2026-06-05 06:10 UTCEPSS rescore
  71. 2026-06-04 13:11 UTCEPSS rescore
  72. 2026-06-04 13:11 UTCEPSS rescore
  73. 2026-06-02 20:12 UTCEPSS rescore
  74. 2026-06-02 20:12 UTCEPSS rescore
  75. 2026-06-01 13:51 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-21840?
CVE-2025-21840 is a medium vulnerability published on March 7, 2025. In the Linux kernel, the following vulnerability has been resolved: thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header The intel-lpmd tool [1], which uses the THERMALGENLATTRCPUCAPABILITY attribute to receive HFI events from kernel space, encounters a segmentation fault…
When was CVE-2025-21840 disclosed?
CVE-2025-21840 was first published in the National Vulnerability Database on March 7, 2025, with the most recent update on October 29, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21840 actively exploited?
CVE-2025-21840 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 89.5% of all scored CVEs.
What is the CVSS score of CVE-2025-21840?
CVE-2025-21840 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21840?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21840, 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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2025-21840

Explore →

Is Your Infrastructure Affected by CVE-2025-21840?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.