CVE-2026-64431

HIGHPre-NVD 7.87.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-25. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

ntfs: avoid calling post_write_mst_fixup() for invalid index_block

ntfs_icx_ib_sync_write() calls post_write_mst_fixup() when ntfs_ib_write() returns an error, intending to restore the buffer after a failed write.

However, ntfs_ib_write() returns an error immediately if pre_write_mst_fixup() validation fails. The caller, ntfs_icx_ib_sync_write(), interprets any error as a write failure requiring rollback. It does not differentiate between I/O errors and validation failures, and calls post_write_mst_fixup() anyway.

Since post_write_mst_fixup() assumes that the index_block contents is correct, it doesn't perform the boundary checks, which results in out-of-bounds memory access.

An attacker can craft a malicious NTFS image with:

  • large index_block.usa_ofs offset, pointing outside the ntfs_record
  • index_block.usa_count = 0, causing integer underflow
  • or index_block.usa_count larger than actual number of sectors in the
ntfs_record, causing out-of-bounds access

KASAN reports describing the memory corruption: ================================================================== BUG: KASAN: slab-out-of-bounds in post_write_mst_fixup+0x19c/0x1d0 Read of size 2 at addr ffff8881586c9018 by task p/9428 Call Trace: dump_stack_lvl+0x100/0x190 print_report+0x139/0x4ad ? post_write_mst_fixup+0x19c/0x1d0 ? __virt_addr_valid+0x262/0x500 ? post_write_mst_fixup+0x19c/0x1d0 kasan_report+0xe4/0x1d0 ? post_write_mst_fixup+0x19c/0x1d0 post_write_mst_fixup+0x19c/0x1d0 ntfs_icx_ib_sync_write+0x179/0x220 ntfs_inode_sync_filename+0x83d/0x1080 __ntfs_write_inode+0x1049/0x1480 ntfs_file_fsync+0x131/0x9b0 ================================================================== BUG: KASAN: slab-out-of-bounds in post_write_mst_fixup+0x1aa/0x1d0 Write of size 2 at addr ffff8881586c91fe by task p/9428 Call Trace: dump_stack_lvl+0x100/0x190 print_report+0x139/0x4ad ? post_write_mst_fixup+0x1aa/0x1d0 ? __virt_addr_valid+0x262/0x500 ? post_write_mst_fixup+0x1aa/0x1d0 kasan_report+0xe4/0x1d0 ? post_write_mst_fixup+0x1aa/0x1d0 post_write_mst_fixup+0x1aa/0x1d0 ntfs_icx_ib_sync_write+0x179/0x220 ntfs_inode_sync_filename+0x83d/0x1080 __ntfs_write_inode+0x1049/0x1480 ntfs_file_fsync+0x131/0x9b0 ==================================================================

Let's move the post_write_mst_fixup() call to ntfs_ib_write(). The ntfs_ib_write() function calls pre_write_mst_fixup() at the beginning. If the index_block contents is invalid, pre_write_mst_fixup() fails and ntfs_ib_write() returns early without calling post_write_mst_fixup() on bad index_block.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
35
EG Risk 35/100

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 (value × EchelonGraph’s weight)
Severity78% × 45%
The EG Score, 7.8 of 10.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
5th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 25, 2026

Last Modified

September 3, 2026

Advisory Details (2)

Auto-updated Jul 27, 2026
Patch available.
Web page

ntfs: avoid calling post_write_mst_fixup() for invalid index_block - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e2018628301a6d9f54e34b0cb417f1688c66df1d
Web page

ntfs: avoid calling post_write_mst_fixup() for invalid index_block - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5b6eedd7cc2936f9238e852b553a1b326105bde8

Vendor Advisories for CVE-2026-64431(1)

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

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (159 versions)
  • every version up to 7.1.4-1: fixed in 7.1.4-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 60× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 246 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 146 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-10-13 11:41 UTCEG score recompute
  3. 2026-10-13 11:41 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  4. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-10-12 15:48 UTCEG score recompute
  6. 2026-10-11 19:32 UTCEG score recompute
  7. 2026-10-11 16:47 UTCEG score recompute
  8. 2026-10-11 14:09 UTCEG score recompute
  9. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  10. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  14. 2026-10-07 04:26 UTCEG score recompute
  15. 2026-10-07 04:26 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  16. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  17. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  18. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-10-04 07:29 UTCEG score recompute
  20. 2026-10-04 07:29 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  21. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-10-02 18:33 UTCEG score recompute
  23. 2026-10-02 18:33 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  24. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  25. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 5th percentile
Show 75 more
  1. 2026-10-01 15:45 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  2. 2026-10-01 04:02 UTCEG score recompute
  3. 2026-10-01 04:02 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  4. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-09-29 08:01 UTCEG score recompute
  6. 2026-09-29 08:01 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  7. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-09-28 04:09 UTCEG score recompute
  9. 2026-09-28 04:09 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  10. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-09-25 07:40 UTCEG score recompute
  12. 2026-09-25 07:40 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  13. 2026-09-24 09:41 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  14. 2026-09-23 22:07 UTCEG score recompute
  15. 2026-09-23 22:07 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  16. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  17. 2026-09-23 09:24 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  18. 2026-09-22 21:58 UTCEG score recompute
  19. 2026-09-22 21:58 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  20. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  21. 2026-09-20 01:21 UTCEG score recompute
  22. 2026-09-20 01:21 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  23. 2026-09-18 19:40 UTCEG score recompute
  24. 2026-09-18 19:40 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  25. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  26. 2026-09-18 02:43 UTCEG score recompute
  27. 2026-09-18 02:43 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  28. 2026-09-17 01:52 UTCEG score recompute
  29. 2026-09-17 01:52 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  30. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  31. 2026-09-16 06:25 UTCEG score recompute
  32. 2026-09-16 06:25 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  33. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  34. 2026-09-15 09:21 UTCEG score recompute
  35. 2026-09-15 09:21 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  36. 2026-09-14 08:50 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  37. 2026-09-13 21:24 UTCEG score recompute
  38. 2026-09-13 21:24 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  39. 2026-09-13 08:12 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  40. 2026-09-12 20:46 UTCEG score recompute
  41. 2026-09-12 20:46 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  42. 2026-09-12 09:12 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  43. 2026-09-11 20:56 UTCEG score recompute
  44. 2026-09-11 20:56 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  45. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  46. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  47. 2026-09-11 09:29 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  48. 2026-09-10 22:03 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  49. 2026-09-10 10:29 UTCEG score recompute
  50. 2026-09-10 10:29 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  51. 2026-09-09 08:33 UTCEG score recompute
  52. 2026-09-09 08:33 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  53. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  54. 2026-09-07 21:13 UTCEG score recompute
  55. 2026-09-07 21:13 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  56. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  57. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  58. 2026-09-06 07:57 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  59. 2026-09-05 19:19 UTCEG score recompute
  60. 2026-09-05 19:19 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  61. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  62. 2026-09-05 05:58 UTCEG score recompute
  63. 2026-09-05 05:58 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  64. 2026-09-04 12:39 UTCEG score recompute
  65. 2026-09-04 12:39 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  66. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  67. 2026-09-03 18:49 UTCEG score recompute
  68. 2026-09-03 18:49 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  69. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  70. 2026-09-01 23:10 UTCEG score recompute
  71. 2026-09-01 23:09 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8
  72. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  73. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  74. 2026-08-30 22:56 UTCEG score recompute
  75. 2026-08-30 22:56 UTCGHSA enrichmentGHSA-7v8v-8486-fvc6 · GitHub severity HIGH · GitHub CVSS 7.8

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-64431?
CVE-2026-64431 is a high-severity vulnerability; its CVE record was published on July 25, 2026. In the Linux kernel, the following vulnerability has been resolved: ntfs: avoid calling postwritemstfixup() for invalid indexblock ntfsicxibsyncwrite() calls postwritemstfixup() when ntfsib_write() returns an error, intending to restore the buffer after a failed write. However, ntfsibwrite()…
When was the CVE record for CVE-2026-64431 published?
The CVE record for CVE-2026-64431 was published on July 25, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 3, 2026; the record at its source may have been updated since.
Is CVE-2026-64431 actively exploited?
CVE-2026-64431 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-64431?
CVE-2026-64431 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-64431?
A fix for CVE-2026-64431 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-64431 are linked in the Vendor Advisories panel on this page.

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