CVE-2026-64257

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-25. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: 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:

smb: client: reject overlapping data areas in SMB2 responses

Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception.

Track data area overlap separately and reject such responses before applying the length compatibility exceptions.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: 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
Severity91% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
49%
KEV
Not listed

Published

July 25, 2026

Last Modified

August 17, 2026

Advisory Details (6)

Auto-updated Aug 29, 2026
No patch confirmed yet.
generic

smb: client: reject overlapping data areas in SMB2 responses - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83
generic

smb: client: reject overlapping data areas in SMB2 responses - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe
generic

smb: client: reject overlapping data areas in SMB2 responses - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460
generic

smb: client: reject overlapping data areas in SMB2 responses - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f
generic

smb: client: reject overlapping data areas in SMB2 responses - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7
generic

smb: client: reject overlapping data areas in SMB2 responses - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775

Vendor Advisories for CVE-2026-64257(1)

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

Data Freshness Timeline

(refreshed 40× in last 7d / 223× 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 271 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-64257?
CVE-2026-64257 is a critical vulnerability published on July 25, 2026. In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without…
When was CVE-2026-64257 disclosed?
CVE-2026-64257 was first published in the National Vulnerability Database on July 25, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64257 actively exploited?
CVE-2026-64257 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 51.1% of all scored CVEs.
What is the CVSS score of CVE-2026-64257?
CVE-2026-64257 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-64257?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64257, 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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