CVE-2025-21646

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 — 4 sources updated this week
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

A fix is available — apply it.

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

afs: Fix the maximum cell name length

The kafs filesystem limits the maximum length of a cell to 256 bytes, but a problem occurs if someone actually does that: kafs tries to create a directory under /proc/net/afs/ with the name of the cell, but that fails with a warning:

WARNING: CPU: 0 PID: 9 at fs/proc/generic.c:405

because procfs limits the maximum filename length to 255.

However, the DNS limits the maximum lookup length and, by extension, the maximum cell name, to 255 less two (length count and trailing NUL).

Fix this by limiting the maximum acceptable cellname length to 253. This also allows us to be sure we can create the "/afs/./" mountpoint too.

Further, split the YFS VL record cell name maximum to be the 256 allowed by the protocol and ignore the record retrieved by YFSVL.GetCellName if it exceeds 253.

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
36%
KEV
Not listed

Published

January 19, 2025

Last Modified

August 5, 2026

Advisory Details (8)

Auto-updated Jul 30, 2026
Patch available.
generic Patch Available

[SECURITY] [DLA 4075-1] linux security update

https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
generic Patch Available

[SECURITY] [DLA 4076-1] linux-6.1 security update

https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
generic

afs: Fix the maximum cell name length - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/aabe47cf5ac5e1db2ae0635f189d836f67024904
generic

afs: Fix the maximum cell name length - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9340385468d056bb700b8f28df236b81fc86a079
generic

afs: Fix the maximum cell name length - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8fd56ad6e7c90ac2bddb0741c6b248c8c5d56ac8
generic

afs: Fix the maximum cell name length - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7cb3e77e9b4e6ffa325a5559393d3283c9af3d01
generic

afs: Fix the maximum cell name length - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7922b1f058fe24a93730511dd0ae2e1630920096
generic

afs: Fix the maximum cell name length - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7673030efe0f8ca1056d3849d61784c6caa052af

Vendor Advisories for CVE-2025-21646(1)

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

Patch Availability(29)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-24.04-edge (6.11.0-21.21) @ oracular2026-05-30ubuntu
ubuntulinux-tools-nvidia-tegra-rt (5.15.0.1033.33) @ jammy2026-05-30ubuntu
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-tools-oem-24.04b (6.11.0-1017.17) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-edge (5.15.0.1077.83~20.04.1) @ focal2026-05-30ubuntu
ubuntulinux-tools-kvm (5.15.0.1076.72) @ jammy2026-05-30ubuntu
ubuntulinux-xilinx-zynqmp-tools-host (5.15.0-1044.48) @ jammy2026-05-30ubuntu
ubuntulinux-tools-realtime (5.15.0.1080.83) @ jammy2026-05-30ubuntu
ubuntulinux-virtual-hwe-20.04-edge (5.15.0.136.147~20.04.1) @ focal2026-05-30ubuntu
ubuntulinux-tools-azure-fde-edge (5.15.0.1086.95~20.04.1.61) @ focal2026-05-30ubuntu
ubuntulinux-tools-gcp-fips (5.15.0.1079.69) @ jammy2026-05-30ubuntu
ubuntulinux-tools-raspi (6.11.0-1010.10) @ oracular2026-05-30ubuntu
ubuntulinux-tools-gcp-edge (5.15.0.1081.90~20.04.1) @ focal2026-05-30ubuntu
ubuntulinux-tools-ibm-edge (5.15.0.1074.77~20.04.1) @ focal2026-05-30ubuntu
ubuntulinux-tools-intel-iotg-edge (5.15.0.1077.83~20.04.1) @ focal2026-05-30ubuntu
ubuntulinux-tools-lowlatency-hwe-22.04-edge (6.8.0-60.63.1~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k (6.8.0-1028.31.1) @ noble2026-05-30ubuntu
ubuntulinux-tools-realtime (6.8.1-1022.23) @ noble2026-05-30ubuntu
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-azure-nvidia (6.8.0-1016.17) @ noble2026-05-30ubuntu
ubuntulinux-tools-raspi (6.8.0-1028.32) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-edge (6.8.0-1026.27~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-gcp-edge (6.8.0-1030.32~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-raspi-realtime (6.8.0-2023.24) @ noble2026-05-30ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-60.63~22.04.1) @ jammy2026-05-30ubuntu
redhatkernel-0:5.14.0-570.12.1.el9_62025-05-13redhat
linuxKernel @ 5.10.234—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.

Additional Vendor Advisories

(24)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 10× 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 107 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. 2026-08-05 14:06 UTCEG score recompute
  5. 2026-08-05 14:06 UTCVendor advisory
  6. 2026-08-05 14:06 UTCGHSA enrichment
  7. 2026-08-04 15:09 UTCEPSS rescore
  8. 2026-08-04 10:37 UTCEPSS rescore
  9. 2026-08-03 10:35 UTCEPSS rescore
  10. 2026-08-02 02:25 UTCEPSS rescore
  11. 2026-08-01 04:15 UTCEPSS rescore
  12. 2026-07-30 16:27 UTCEPSS rescore
  13. 2026-07-30 07:25 UTCEG score recompute
  14. 2026-07-30 07:25 UTCVendor advisory
  15. 2026-07-30 07:25 UTCGHSA enrichment
  16. 2026-07-30 01:29 UTCEPSS rescore
  17. 2026-07-28 15:35 UTCEPSS rescore
  18. 2026-07-27 14:12 UTCEPSS rescore
  19. 2026-07-26 14:53 UTCEPSS rescore
  20. 2026-07-24 17:41 UTCOSV refresh
  21. 2026-07-23 14:17 UTCEPSS rescore
  22. 2026-07-23 02:50 UTCEG score recompute
  23. 2026-07-22 14:07 UTCEPSS rescore
  24. 2026-07-22 14:07 UTCEPSS rescore
  25. 2026-07-21 15:24 UTCEPSS rescore
Show 75 more
  1. 2026-07-20 17:07 UTCEPSS rescore
  2. 2026-07-19 14:30 UTCEPSS rescore
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  4. 2026-07-18 10:03 UTCEPSS rescore
  5. 2026-07-16 17:02 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 12:51 UTCOSV refresh
  19. 2026-07-06 16:26 UTCEPSS rescore
  20. 2026-07-05 02:30 UTCEPSS rescore
  21. 2026-07-04 06:30 UTCEPSS rescore
  22. 2026-07-01 15:06 UTCEPSS rescore
  23. 2026-06-30 23:21 UTCEPSS rescore
  24. 2026-06-30 23:21 UTCEPSS rescore
  25. 2026-06-29 14:06 UTCEPSS rescore
  26. 2026-06-28 14:07 UTCEPSS rescore
  27. 2026-06-28 14:07 UTCEPSS rescore
  28. 2026-06-28 04:55 UTCEPSS rescore
  29. 2026-06-28 04:55 UTCEPSS rescore
  30. 2026-06-27 03:08 UTCEPSS rescore
  31. 2026-06-27 03:08 UTCEPSS rescore
  32. 2026-06-25 13:49 UTCEPSS rescore
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  34. 2026-06-24 14:04 UTCEPSS rescore
  35. 2026-06-24 14:04 UTCEPSS rescore
  36. 2026-06-23 21:32 UTCEPSS rescore
  37. 2026-06-23 21:32 UTCEPSS rescore
  38. 2026-06-22 14:25 UTCEPSS rescore
  39. 2026-06-22 14:25 UTCEPSS rescore
  40. 2026-06-21 14:56 UTCEPSS rescore
  41. 2026-06-21 14:56 UTCEPSS rescore
  42. 2026-06-21 01:59 UTCEPSS rescore
  43. 2026-06-21 01:59 UTCEPSS rescore
  44. 2026-06-19 19:25 UTCEPSS rescore
  45. 2026-06-19 19:25 UTCEPSS rescore
  46. 2026-06-19 00:05 UTCOSV refresh
  47. 2026-06-18 17:52 UTCEPSS rescore
  48. 2026-06-18 17:52 UTCEPSS rescore
  49. 2026-06-17 17:52 UTCEPSS rescore
  50. 2026-06-16 17:52 UTCEPSS rescore
  51. 2026-06-16 17:52 UTCEPSS rescore
  52. 2026-06-15 17:48 UTCEPSS rescore
  53. 2026-06-13 22:59 UTCEPSS rescore
  54. 2026-06-12 23:11 UTCEPSS rescore
  55. 2026-06-11 13:59 UTCEPSS rescore
  56. 2026-06-10 22:18 UTCEPSS rescore
  57. 2026-06-10 13:22 UTCEPSS rescore
  58. 2026-06-08 14:16 UTCEPSS rescore
  59. 2026-06-08 14:16 UTCEPSS rescore
  60. 2026-06-07 15:24 UTCEPSS rescore
  61. 2026-06-07 15:24 UTCEPSS rescore
  62. 2026-06-06 13:47 UTCEPSS rescore
  63. 2026-06-06 13:47 UTCEPSS rescore
  64. 2026-06-05 22:46 UTCEPSS rescore
  65. 2026-06-05 22:46 UTCEPSS rescore
  66. 2026-06-05 06:10 UTCEPSS rescore
  67. 2026-06-05 06:10 UTCEPSS rescore
  68. 2026-06-04 13:11 UTCEPSS rescore
  69. 2026-06-04 13:11 UTCEPSS rescore
  70. 2026-06-02 20:12 UTCEPSS rescore
  71. 2026-06-02 20:12 UTCEPSS rescore
  72. 2026-06-01 13:51 UTCEPSS rescore
  73. 2026-06-01 13:51 UTCEPSS rescore
  74. 2026-05-31 22:30 UTCEPSS rescore
  75. 2026-05-31 22:30 UTCEPSS rescore

Frequently asked(5)

What is CVE-2025-21646?
CVE-2025-21646 is a medium vulnerability published on January 19, 2025. In the Linux kernel, the following vulnerability has been resolved: afs: Fix the maximum cell name length The kafs filesystem limits the maximum length of a cell to 256 bytes, but a problem occurs if someone actually does that: kafs tries to create a directory under /proc/net/afs/ with the name of…
When was CVE-2025-21646 disclosed?
CVE-2025-21646 was first published in the National Vulnerability Database on January 19, 2025, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21646 actively exploited?
CVE-2025-21646 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 64.1% of all scored CVEs.
What is the CVSS score of CVE-2025-21646?
CVE-2025-21646 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21646?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21646, 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

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