CVE-2025-40295

UNRATEDCVSS · not yet scored
—
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: None knownExposed: 0

A fix is available — apply it.

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

fscrypt: fix left shift underflow when inode->i_blkbits > PAGE_SHIFT

When simulating an nvme device on qemu with both logical_block_size and physical_block_size set to 8 KiB, an error trace appears during partition table reading at boot time. The issue is caused by inode->i_blkbits being larger than PAGE_SHIFT, which leads to a left shift of -1 and triggering a UBSAN warning.

[ 2.697306] ------------[ cut here ]------------ [ 2.697309] UBSAN: shift-out-of-bounds in fs/crypto/inline_crypt.c:336:37 [ 2.697311] shift exponent -1 is negative [ 2.697315] CPU: 3 UID: 0 PID: 274 Comm: (udev-worker) Not tainted 6.18.0-rc2+ #34 PREEMPT(voluntary) [ 2.697317] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 2.697320] Call Trace: [ 2.697324] [ 2.697325] dump_stack_lvl+0x76/0xa0 [ 2.697340] dump_stack+0x10/0x20 [ 2.697342] __ubsan_handle_shift_out_of_bounds+0x1e3/0x390 [ 2.697351] bh_get_inode_and_lblk_num.cold+0x12/0x94 [ 2.697359] fscrypt_set_bio_crypt_ctx_bh+0x44/0x90 [ 2.697365] submit_bh_wbc+0xb6/0x190 [ 2.697370] block_read_full_folio+0x194/0x270 [ 2.697371] ? __pfx_blkdev_get_block+0x10/0x10 [ 2.697375] ? __pfx_blkdev_read_folio+0x10/0x10 [ 2.697377] blkdev_read_folio+0x18/0x30 [ 2.697379] filemap_read_folio+0x40/0xe0 [ 2.697382] filemap_get_pages+0x5ef/0x7a0 [ 2.697385] ? mmap_region+0x63/0xd0 [ 2.697389] filemap_read+0x11d/0x520 [ 2.697392] blkdev_read_iter+0x7c/0x180 [ 2.697393] vfs_read+0x261/0x390 [ 2.697397] ksys_read+0x71/0xf0 [ 2.697398] __x64_sys_read+0x19/0x30 [ 2.697399] x64_sys_call+0x1e88/0x26a0 [ 2.697405] do_syscall_64+0x80/0x670 [ 2.697410] ? __x64_sys_newfstat+0x15/0x20 [ 2.697414] ? x64_sys_call+0x204a/0x26a0 [ 2.697415] ? do_syscall_64+0xb8/0x670 [ 2.697417] ? irqentry_exit_to_user_mode+0x2e/0x2a0 [ 2.697420] ? irqentry_exit+0x43/0x50 [ 2.697421] ? exc_page_fault+0x90/0x1b0 [ 2.697422] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 2.697425] RIP: 0033:0x75054cba4a06 [ 2.697426] Code: 5d e8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 75 19 83 e2 39 83 fa 08 75 11 e8 26 ff ff ff 66 0f 1f 44 00 00 48 8b 45 10 0f 05 <48> 8b 5d f8 c9 c3 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 48 83 ec 08 [ 2.697427] RSP: 002b:00007fff973723a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 [ 2.697430] RAX: ffffffffffffffda RBX: 00005ea9a2c02760 RCX: 000075054cba4a06 [ 2.697432] RDX: 0000000000002000 RSI: 000075054c190000 RDI: 000000000000001b [ 2.697433] RBP: 00007fff973723c0 R08: 0000000000000000 R09: 0000000000000000 [ 2.697434] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 [ 2.697434] R13: 00005ea9a2c027c0 R14: 00005ea9a2be5608 R15: 00005ea9a2be55f0 [ 2.697436] [ 2.697436] ---[ end trace ]---

This situation can happen for block devices because when CONFIG_TRANSPARENT_HUGEPAGE is enabled, the maximum logical_block_size is 64 KiB. set_init_blocksize() then sets the block device inode->i_blkbits to 13, which is within this limit.

File I/O does not trigger this problem because for filesystems that do not support the FS_LBS feature, sb_set_blocksize() prevents sb->s_blocksize_bits from being larger than PAGE_SHIFT. During inode allocation, alloc_inode()->inode_init_always() assigns inode->i_blkbits from sb->s_blocksize_bits. Currently, only xfs_fs_type has the FS_LBS flag, and since xfs I/O paths do not reach submit_bh_wbc(), it does not hit the left-shift underflow issue.

[EB: use folio_pos() and consolidate the two shifts by i_blkbits]

CVSS v3
—
EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
—
EG Risk
—
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

December 8, 2025

Last Modified

April 15, 2026

References (2)

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-oracle-64k-6.17 (6.17.0-1007.7) @ questing2026-05-21ubuntu
ubuntulinux-virtual-hwe-24.04-edge (6.17.0-14.14) @ questing2026-05-21ubuntu
ubuntulinux-tools-gcp-64k-6.17 (6.17.0-1007.7) @ questing2026-05-21ubuntu
ubuntulinux-tools-oem-6.17 (6.17.0-1011.11) @ noble2026-05-21ubuntu
ubuntulinux-tools-azure-6.17 (6.17.0-1008.8) @ questing2026-05-21ubuntu
linuxKernel @ 6.17.8—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.

All Vendor Advisories

(5)

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 7× in last 7d / 37× 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 133 total refreshes for this CVE.

  1. 2026-08-04 15:09 UTCEPSS rescore
  2. 2026-08-04 10:37 UTCEPSS rescore
  3. 2026-08-03 10:35 UTCEPSS rescore
  4. 2026-08-02 02:26 UTCEPSS rescore
  5. 2026-08-01 04:15 UTCEPSS rescore
  6. 2026-07-30 16:27 UTCEPSS rescore
  7. 2026-07-30 01:29 UTCEPSS rescore
  8. 2026-07-28 15:35 UTCEPSS rescore
  9. 2026-07-27 06:09 UTCOSV refresh
  10. 2026-07-26 14:54 UTCEPSS rescore
  11. 2026-07-25 14:17 UTCEPSS rescore
  12. 2026-07-25 14:17 UTCEPSS rescore
  13. 2026-07-24 14:17 UTCEPSS rescore
  14. 2026-07-23 02:55 UTCEG score recompute
  15. 2026-07-22 14:07 UTCEPSS rescore
  16. 2026-07-22 14:07 UTCEPSS rescore
  17. 2026-07-21 15:24 UTCEPSS rescore
  18. 2026-07-20 17:07 UTCEPSS rescore
  19. 2026-07-19 14:30 UTCEPSS rescore
  20. 2026-07-19 14:30 UTCEPSS rescore
  21. 2026-07-19 02:28 UTCEPSS rescore
  22. 2026-07-19 02:28 UTCEPSS rescore
  23. 2026-07-18 10:04 UTCEPSS rescore
  24. 2026-07-18 10:04 UTCEPSS rescore
  25. 2026-07-16 17:02 UTCEPSS rescore
Show 75 more
  1. 2026-07-15 01:59 UTCEPSS rescore
  2. 2026-07-15 01:59 UTCEPSS rescore
  3. 2026-07-13 22:29 UTCEPSS rescore
  4. 2026-07-13 22:29 UTCEPSS rescore
  5. 2026-07-13 06:12 UTCEPSS rescore
  6. 2026-07-12 05:46 UTCEPSS rescore
  7. 2026-07-11 08:27 UTCEPSS rescore
  8. 2026-07-11 08:27 UTCEPSS rescore
  9. 2026-07-10 00:45 UTCOSV refresh
  10. 2026-07-09 19:09 UTCEPSS rescore
  11. 2026-07-09 19:09 UTCEPSS rescore
  12. 2026-07-07 13:45 UTCEPSS rescore
  13. 2026-07-06 16:27 UTCEPSS rescore
  14. 2026-07-06 16:27 UTCEPSS rescore
  15. 2026-07-06 02:23 UTCEPSS rescore
  16. 2026-07-05 02:30 UTCEPSS rescore
  17. 2026-07-04 06:30 UTCEPSS rescore
  18. 2026-07-01 15:06 UTCEPSS rescore
  19. 2026-07-01 15:06 UTCEPSS rescore
  20. 2026-06-30 23:22 UTCEPSS rescore
  21. 2026-06-30 23:22 UTCEPSS rescore
  22. 2026-06-29 14:06 UTCEPSS rescore
  23. 2026-06-29 14:06 UTCEPSS rescore
  24. 2026-06-28 14:07 UTCEPSS rescore
  25. 2026-06-28 14:07 UTCEPSS rescore
  26. 2026-06-28 04:55 UTCEPSS rescore
  27. 2026-06-28 04:55 UTCEPSS rescore
  28. 2026-06-27 03:08 UTCEPSS rescore
  29. 2026-06-27 03:08 UTCEPSS rescore
  30. 2026-06-25 13:49 UTCEPSS rescore
  31. 2026-06-25 13:49 UTCEPSS rescore
  32. 2026-06-24 14:04 UTCEPSS rescore
  33. 2026-06-24 14:04 UTCEPSS rescore
  34. 2026-06-23 21:32 UTCEPSS rescore
  35. 2026-06-23 21:32 UTCEPSS rescore
  36. 2026-06-22 14:25 UTCEPSS rescore
  37. 2026-06-22 14:25 UTCEPSS rescore
  38. 2026-06-21 14:56 UTCEPSS rescore
  39. 2026-06-21 14:56 UTCEPSS rescore
  40. 2026-06-21 11:01 UTCOSV refresh
  41. 2026-06-21 01:59 UTCEPSS rescore
  42. 2026-06-21 01:59 UTCEPSS rescore
  43. 2026-06-19 19:25 UTCEPSS rescore
  44. 2026-06-19 19:25 UTCEPSS rescore
  45. 2026-06-18 17:52 UTCEPSS rescore
  46. 2026-06-18 17:52 UTCEPSS rescore
  47. 2026-06-17 17:52 UTCEPSS rescore
  48. 2026-06-16 17:52 UTCEPSS rescore
  49. 2026-06-16 17:52 UTCEPSS rescore
  50. 2026-06-14 23:17 UTCEPSS rescore
  51. 2026-06-13 23:00 UTCEPSS rescore
  52. 2026-06-12 23:11 UTCEPSS rescore
  53. 2026-06-11 14:00 UTCEPSS rescore
  54. 2026-06-10 22:18 UTCEPSS rescore
  55. 2026-06-10 13:22 UTCEPSS rescore
  56. 2026-06-08 14:16 UTCEPSS rescore
  57. 2026-06-08 14:16 UTCEPSS rescore
  58. 2026-06-07 15:24 UTCEPSS rescore
  59. 2026-06-06 13:47 UTCEPSS rescore
  60. 2026-06-06 13:47 UTCEPSS rescore
  61. 2026-06-05 22:46 UTCEPSS rescore
  62. 2026-06-05 22:46 UTCEPSS rescore
  63. 2026-06-05 06:10 UTCEPSS rescore
  64. 2026-06-05 06:10 UTCEPSS rescore
  65. 2026-06-04 13:12 UTCEPSS rescore
  66. 2026-06-04 13:12 UTCEPSS rescore
  67. 2026-06-02 20:12 UTCEPSS rescore
  68. 2026-06-02 03:09 UTCOSV refresh
  69. 2026-06-01 13:51 UTCEPSS rescore
  70. 2026-06-01 13:51 UTCEPSS rescore
  71. 2026-05-31 22:30 UTCEPSS rescore
  72. 2026-05-31 22:30 UTCEPSS rescore
  73. 2026-05-31 00:16 UTCEPSS rescore
  74. 2026-05-29 13:44 UTCEPSS rescore
  75. 2026-05-28 13:44 UTCEPSS rescore

Frequently asked(4)

What is CVE-2025-40295?
CVE-2025-40295 is a publicly disclosed vulnerability published on December 8, 2025. In the Linux kernel, the following vulnerability has been resolved: fscrypt: fix left shift underflow when inode->iblkbits > PAGESHIFT When simulating an nvme device on qemu with both logicalblocksize and physicalblocksize set to 8 KiB, an error trace appears during partition table reading at boot…
When was CVE-2025-40295 disclosed?
CVE-2025-40295 was first published in the National Vulnerability Database on December 8, 2025, with the most recent update on April 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-40295 actively exploited?
CVE-2025-40295 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 89.9% of all scored CVEs.
How do I remediate CVE-2025-40295?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-40295, 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-2025-40295

Explore →

Is Your Infrastructure Affected by CVE-2025-40295?

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

Start Free Scan →Browse All CVEs