CVE-2026-43288

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-05-08. 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

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:

ext4: move ext4_percpu_param_init() before ext4_mb_init()

When running kvm-xfstests -c ext4/1k -C 1 generic/383 with the DOUBLE_CHECK macro defined, the following panic is triggered:

================================================================== EXT4-fs error (device vdc): ext4_validate_block_bitmap:423: comm mount: bg 0: bad block bitmap checksum BUG: unable to handle page fault for address: ff110000fa2cc000 PGD 3e01067 P4D 3e02067 PUD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 2386 Comm: mount Tainted: G W 6.18.0-gba65a4e7120a-dirty #1152 PREEMPT(none) RIP: 0010:percpu_counter_add_batch+0x13/0xa0 Call Trace: ext4_mark_group_bitmap_corrupted+0xcb/0xe0 ext4_validate_block_bitmap+0x2a1/0x2f0 ext4_read_block_bitmap+0x33/0x50 mb_group_bb_bitmap_alloc+0x33/0x80 ext4_mb_add_groupinfo+0x190/0x250 ext4_mb_init_backend+0x87/0x290 ext4_mb_init+0x456/0x640 __ext4_fill_super+0x1072/0x1680 ext4_fill_super+0xd3/0x280 get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x29/0xd0 vfs_cmd_create+0x59/0xe0 __do_sys_fsconfig+0x4f6/0x6b0 do_syscall_64+0x50/0x1f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ==================================================================

This issue can be reproduced using the following commands: mkfs.ext4 -F -q -b 1024 /dev/sda 5G tune2fs -O quota,project /dev/sda mount /dev/sda /tmp/test

With DOUBLE_CHECK defined, mb_group_bb_bitmap_alloc() reads and validates the block bitmap. When the validation fails, ext4_mark_group_bitmap_corrupted() attempts to update sbi->s_freeclusters_counter. However, this percpu_counter has not been initialized yet at this point, which leads to the panic described above.

Fix this by moving the execution of ext4_percpu_param_init() to occur before ext4_mb_init(), ensuring the per-CPU counters are initialized before they are used.

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
3.0%
KEV
Not listed

Published

May 8, 2026

Last Modified

May 15, 2026

Advisory Details (5)

Auto-updated Jun 15, 2026
No patch confirmed yet.
generic

ext4: move ext4_percpu_param_init() before ext4_mb_init() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bf5b609524497c195f801cd5707252384aed8149
generic

ext4: move ext4_percpu_param_init() before ext4_mb_init() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/aec095f3cc6cf209effd93278ce35be27db81d73
generic

ext4: move ext4_percpu_param_init() before ext4_mb_init() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9e9fb259bcddf459a0168f4a964e979e500a68a5
generic

ext4: move ext4_percpu_param_init() before ext4_mb_init() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/270564513489d98b721a1e4a10017978d5213bff
generic

ext4: move ext4_percpu_param_init() before ext4_mb_init() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0d5fcb063cdabb9aeaa8554b7fedad2092c4150e

Vendor Advisories for CVE-2026-43288(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 42× 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 102 total refreshes for this CVE.

  1. 2026-07-12 05:46 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:16 UTCEPSS rescore
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  9. 2026-06-29 14:06 UTCEPSS rescore
  10. 2026-06-28 14:07 UTCEPSS rescore
  11. 2026-06-28 05:11 UTCEG score recompute
  12. 2026-06-28 05:11 UTCGHSA enrichment
  13. 2026-06-28 04:56 UTCEPSS rescore
  14. 2026-06-27 03:08 UTCEPSS rescore
  15. 2026-06-26 21:36 UTCEG score recompute
  16. 2026-06-26 21:36 UTCGHSA enrichment
  17. 2026-06-25 13:49 UTCEPSS rescore
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  19. 2026-06-24 14:05 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
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  1. 2026-06-19 19:25 UTCEPSS rescore
  2. 2026-06-18 17:52 UTCEPSS rescore
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  4. 2026-06-17 17:53 UTCEPSS rescore
  5. 2026-06-17 02:06 UTCEG score recompute
  6. 2026-06-17 02:06 UTCGHSA enrichment
  7. 2026-06-16 17:52 UTCEPSS rescore
  8. 2026-06-15 17:49 UTCEPSS rescore
  9. 2026-06-15 02:27 UTCEG score recompute
  10. 2026-06-15 02:27 UTCGHSA enrichment
  11. 2026-06-14 03:05 UTCEG score recompute
  12. 2026-06-14 03:04 UTCGHSA enrichment
  13. 2026-06-13 23:00 UTCEPSS rescore
  14. 2026-06-13 00:44 UTCEG score recompute
  15. 2026-06-13 00:44 UTCGHSA enrichment
  16. 2026-06-12 23:12 UTCEPSS rescore
  17. 2026-06-12 23:12 UTCEPSS rescore
  18. 2026-06-12 01:20 UTCEG score recompute
  19. 2026-06-12 01:20 UTCGHSA enrichment
  20. 2026-06-11 14:00 UTCEPSS rescore
  21. 2026-06-11 01:56 UTCEG score recompute
  22. 2026-06-11 01:56 UTCGHSA enrichment
  23. 2026-06-10 22:18 UTCEPSS rescore
  24. 2026-06-10 13:22 UTCEPSS rescore
  25. 2026-06-10 13:22 UTCEPSS rescore
  26. 2026-06-10 02:34 UTCEG score recompute
  27. 2026-06-10 02:34 UTCGHSA enrichment
  28. 2026-06-09 03:12 UTCEG score recompute
  29. 2026-06-09 03:12 UTCGHSA enrichment
  30. 2026-06-08 14:17 UTCEPSS rescore
  31. 2026-06-08 14:17 UTCEPSS rescore
  32. 2026-06-08 03:49 UTCEG score recompute
  33. 2026-06-08 03:49 UTCGHSA enrichment
  34. 2026-06-07 15:25 UTCEPSS rescore
  35. 2026-06-07 15:25 UTCEPSS rescore
  36. 2026-06-07 04:27 UTCEG score recompute
  37. 2026-06-07 04:27 UTCGHSA enrichment
  38. 2026-06-06 13:47 UTCEPSS rescore
  39. 2026-06-06 13:47 UTCEPSS rescore
  40. 2026-06-06 05:04 UTCEG score recompute
  41. 2026-06-06 05:04 UTCGHSA enrichment
  42. 2026-06-05 22:47 UTCEPSS rescore
  43. 2026-06-05 06:10 UTCEPSS rescore
  44. 2026-06-05 06:10 UTCEPSS rescore
  45. 2026-06-05 05:41 UTCEG score recompute
  46. 2026-06-05 05:41 UTCGHSA enrichment
  47. 2026-06-04 13:12 UTCEPSS rescore
  48. 2026-06-04 13:12 UTCEPSS rescore
  49. 2026-06-04 06:18 UTCEG score recompute
  50. 2026-06-04 06:18 UTCGHSA enrichment
  51. 2026-06-03 06:54 UTCEG score recompute
  52. 2026-06-03 06:54 UTCGHSA enrichment
  53. 2026-06-02 20:13 UTCEPSS rescore
  54. 2026-06-02 07:31 UTCEG score recompute
  55. 2026-06-02 07:31 UTCGHSA enrichment
  56. 2026-06-01 13:52 UTCEPSS rescore
  57. 2026-06-01 13:52 UTCEPSS rescore
  58. 2026-06-01 08:07 UTCEG score recompute
  59. 2026-06-01 08:07 UTCGHSA enrichment
  60. 2026-05-31 22:30 UTCEPSS rescore
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  62. 2026-05-31 00:16 UTCEPSS rescore
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  64. 2026-05-29 13:44 UTCEPSS rescore
  65. 2026-05-29 13:44 UTCEPSS rescore
  66. 2026-05-28 13:44 UTCEPSS rescore
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  68. 2026-05-27 13:40 UTCEPSS rescore
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  71. 2026-05-26 07:18 UTCEPSS rescore
  72. 2026-05-21 22:43 UTCEPSS rescore
  73. 2026-05-20 22:38 UTCEPSS rescore
  74. 2026-05-20 13:44 UTCEG score recompute
  75. 2026-05-20 13:44 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-43288?
CVE-2026-43288 is a medium vulnerability published on May 8, 2026. In the Linux kernel, the following vulnerability has been resolved: ext4: move ext4percpuparaminit() before ext4mb_init() When running kvm-xfstests -c ext4/1k -C 1 generic/383 with the DOUBLE_CHECK macro defined, the following panic is triggered:…
When was CVE-2026-43288 disclosed?
CVE-2026-43288 was first published in the National Vulnerability Database on May 8, 2026, with the most recent update on May 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43288 actively exploited?
CVE-2026-43288 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-43288?
CVE-2026-43288 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-43288?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43288, 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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