CVE-2026-64257

CRITICALPre-NVD 9.19.1
EchelonGraph scoreMEDIUM confidence

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

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, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-48969 (ENISA EUVD) · GHSA-cfrm-7rjv-hj84 (GitHub Security Advisories)Source: ENISA EUVD

9.1EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

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
9.1CRITICALmedium confidence
EG Risk
41
EG Risk 41/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity91% × 45%
Impact severity (EG Severity): CVSS 9.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.7% × 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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
0.7%
EPSS %ILE
53rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.1): severity, escalated by confirmed exploitation. This CVE's 9.1 is its impact severity (EG Severity), not escalated.

EG Severity
9.1 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

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

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

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

August 17, 2026

Advisory Details (6)

Auto-updated Sep 16, 2026
Fix referenced — no release confirmed yet.
Web page

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
Web page

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
Web page

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
Web page

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
Web page

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
Web page

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 20× in last 7d / 79× 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 454 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 354 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-10-29 11:29 UTCEG score recompute
  3. 2026-10-29 11:29 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  5. 2026-10-28 10:22 UTCEG score recompute
  6. 2026-10-28 10:22 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  8. 2026-10-27 08:20 UTCEG score recompute
  9. 2026-10-27 08:19 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  10. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-10-26 04:57 UTCEG score recompute
  12. 2026-10-26 04:57 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  13. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  14. 2026-10-25 14:12 UTCEG score recompute
  15. 2026-10-25 03:50 UTCEG score recompute
  16. 2026-10-25 03:50 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  17. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  18. 2026-10-24 02:43 UTCEG score recompute
  19. 2026-10-24 02:43 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  20. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  21. 2026-10-23 01:35 UTCEG score recompute
  22. 2026-10-23 01:34 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  23. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-10-22 00:27 UTCEG score recompute
  25. 2026-10-22 00:26 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
Show 75 more
  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  2. 2026-10-20 23:16 UTCEG score recompute
  3. 2026-10-20 23:16 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  5. 2026-10-19 22:09 UTCEG score recompute
  6. 2026-10-19 22:08 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  7. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  8. 2026-10-18 20:55 UTCEG score recompute
  9. 2026-10-18 20:55 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  10. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-10-18 03:22 UTCEG score recompute
  12. 2026-10-17 19:47 UTCEG score recompute
  13. 2026-10-17 19:46 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  15. 2026-10-16 18:38 UTCEG score recompute
  16. 2026-10-16 18:38 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  17. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  18. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  19. 2026-10-15 15:14 UTCEG score recompute
  20. 2026-10-15 15:13 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  21. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  22. 2026-10-14 09:37 UTCEG score recompute
  23. 2026-10-14 09:36 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  24. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  25. 2026-10-13 07:19 UTCEG score recompute
  26. 2026-10-13 07:18 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  27. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  28. 2026-10-12 15:48 UTCEG score recompute
  29. 2026-10-12 06:09 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  30. 2026-10-11 19:32 UTCEG score recompute
  31. 2026-10-11 16:48 UTCEG score recompute
  32. 2026-10-11 14:09 UTCEG score recompute
  33. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  34. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  35. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  36. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  37. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  38. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  39. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  40. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  41. 2026-10-04 12:41 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  42. 2026-10-04 07:41 UTCEG score recompute
  43. 2026-10-04 07:41 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  44. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  45. 2026-10-03 03:16 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  46. 2026-10-02 19:42 UTCEG score recompute
  47. 2026-10-02 19:42 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  48. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  49. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  50. 2026-10-01 12:37 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  51. 2026-10-01 08:38 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  52. 2026-10-01 04:30 UTCEG score recompute
  53. 2026-10-01 04:30 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  54. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  55. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  56. 2026-09-28 12:59 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  57. 2026-09-28 08:33 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  58. 2026-09-28 04:25 UTCEG score recompute
  59. 2026-09-28 04:25 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  60. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  61. 2026-09-25 09:59 UTCEG score recompute
  62. 2026-09-25 09:59 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  63. 2026-09-24 10:25 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  64. 2026-09-24 06:27 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  65. 2026-09-24 02:14 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  66. 2026-09-23 22:15 UTCEG score recompute
  67. 2026-09-23 22:15 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  68. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  69. 2026-09-23 10:06 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  70. 2026-09-23 06:06 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  71. 2026-09-23 02:07 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  72. 2026-09-22 22:08 UTCEG score recompute
  73. 2026-09-22 22:08 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1
  74. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  75. 2026-09-20 05:44 UTCGHSA enrichmentGHSA-cfrm-7rjv-hj84 · GitHub severity CRITICAL · GitHub CVSS 9.1

Frequently asked(5)

What is CVE-2026-64257?
CVE-2026-64257 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-64257 published?
The CVE record for CVE-2026-64257 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 August 17, 2026; the record at its source may have been updated since.
Is CVE-2026-64257 actively exploited?
CVE-2026-64257 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-64257?
CVE-2026-64257 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-64257?
A fix for CVE-2026-64257 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2026-64257 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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