CVE-2026-74521

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 2026-08-15. 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 — 4 sources updated this week
9.1EG
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: 0.4%CVSS: 9.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

ksmbd: use memcmp() to compare ClientGUIDs

ClientGUID is a fixed-size binary value and can contain embedded NUL bytes. strncmp() stops comparing at the first NUL byte, so different ClientGUID values can incorrectly be treated as equal.

Use memcmp() in SMB3 multichannel session binding and FSCTL_VALIDATE_NEGOTIATE_INFO to compare all SMB2_CLIENT_GUID_SIZE bytes.

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.
Exploitation0.4% × 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
0.4%
EPSS %ILE
33rd
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
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-19). 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 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

August 15, 2026

Last Modified

October 3, 2026

Advisory Details (2)

Auto-updated Sep 16, 2026
Patch available.
Web page

ksmbd: use memcmp() to compare ClientGUIDs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e8bb506e6ef749ac0336f3e579d8d02396b7d832
Web page

ksmbd: use memcmp() to compare ClientGUIDs - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d535363299822c5caa543787b21bd5cfa3e41949

Vendor Advisories for CVE-2026-74521(1)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1035.38) @ noble2026-10-20ubuntu

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.

Affected Packages

(4 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (360 versions)
  • every version on: no fix on record
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1, 6.12.107-1~deb12u1
  • every version up to 6.12.111-1~deb12u1: fixed in 6.12.111-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (35 versions)
  • every version up to 6.12.111-1: fixed in 6.12.111-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (165 versions)
  • every version up to 7.1.8-1: fixed in 7.1.8-1
—

All Vendor Advisories

(1)

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 24× in last 7d / 204× 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 473 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 373 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-20 06:01 UTCEG score recompute
  2. 2026-10-20 06:01 UTCVendor advisory
  3. 2026-10-20 06:01 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  5. 2026-10-19 07:36 UTCEG score recompute
  6. 2026-10-19 07:36 UTCVendor advisory
  7. 2026-10-19 07:36 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  8. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  9. 2026-10-18 09:10 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  10. 2026-10-18 03:14 UTCEG score recompute
  11. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  12. 2026-10-17 10:43 UTCEG score recompute
  13. 2026-10-17 10:42 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  14. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  15. 2026-10-16 12:15 UTCEG score recompute
  16. 2026-10-16 12:15 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  17. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  18. 2026-10-15 13:48 UTCEG score recompute
  19. 2026-10-15 13:48 UTCVendor advisory
  20. 2026-10-15 13:48 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  21. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  22. 2026-10-14 08:44 UTCEG score recompute
  23. 2026-10-14 08:43 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  24. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  25. 2026-10-13 04:05 UTCEG score recompute
Show 75 more
  1. 2026-10-13 04:04 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  3. 2026-10-12 15:39 UTCEG score recompute
  4. 2026-10-12 05:39 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  5. 2026-10-11 19:25 UTCEG score recompute
  6. 2026-10-11 16:41 UTCEG score recompute
  7. 2026-10-11 14:00 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  11. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  13. 2026-10-07 06:29 UTCVendor advisory
  14. 2026-10-07 06:29 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  15. 2026-10-07 02:18 UTCVendor advisory
  16. 2026-10-07 02:18 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  17. 2026-10-06 22:02 UTCVendor advisory
  18. 2026-10-06 22:02 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  19. 2026-10-06 17:15 UTCEG score recompute
  20. 2026-10-06 17:15 UTCVendor advisory
  21. 2026-10-06 17:15 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  22. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  23. 2026-10-06 13:12 UTCVendor advisory
  24. 2026-10-06 13:12 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  25. 2026-10-06 09:09 UTCEG score recompute
  26. 2026-10-06 09:09 UTCVendor advisory
  27. 2026-10-06 09:08 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  28. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  29. 2026-10-05 17:27 UTCVendor advisory
  30. 2026-10-05 17:27 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  31. 2026-10-05 12:03 UTCVendor advisory
  32. 2026-10-05 12:03 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  33. 2026-10-05 06:44 UTCVendor advisory
  34. 2026-10-05 06:44 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  35. 2026-10-05 02:01 UTCEG score recompute
  36. 2026-10-05 02:01 UTCVendor advisory
  37. 2026-10-05 02:00 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  38. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  39. 2026-10-04 21:55 UTCVendor advisory
  40. 2026-10-04 21:55 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  41. 2026-10-04 16:27 UTCVendor advisory
  42. 2026-10-04 16:27 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  43. 2026-10-04 11:55 UTCVendor advisory
  44. 2026-10-04 11:54 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  45. 2026-10-04 07:28 UTCVendor advisory
  46. 2026-10-04 07:28 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  47. 2026-10-04 03:24 UTCVendor advisory
  48. 2026-10-04 03:24 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  49. 2026-10-03 19:29 UTCEG score recompute
  50. 2026-10-03 19:29 UTCVendor advisory
  51. 2026-10-03 19:29 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  52. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  53. 2026-10-03 11:35 UTCVendor advisory
  54. 2026-10-03 11:35 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  55. 2026-10-03 00:47 UTCVendor advisory
  56. 2026-10-03 00:47 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  57. 2026-10-02 19:53 UTCEG score recompute
  58. 2026-10-02 19:53 UTCVendor advisory
  59. 2026-10-02 19:53 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  60. 2026-10-02 15:50 UTCVendor advisory
  61. 2026-10-02 15:50 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  62. 2026-10-02 07:02 UTCVendor advisory
  63. 2026-10-02 07:02 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  64. 2026-10-02 01:59 UTCEG score recompute
  65. 2026-10-02 01:59 UTCVendor advisory
  66. 2026-10-02 01:59 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  67. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  68. 2026-10-01 13:57 UTCVendor advisory
  69. 2026-10-01 13:57 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  70. 2026-10-01 09:53 UTCVendor advisory
  71. 2026-10-01 09:53 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  72. 2026-10-01 05:50 UTCVendor advisory
  73. 2026-10-01 05:50 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1
  74. 2026-10-01 01:33 UTCVendor advisory
  75. 2026-10-01 01:33 UTCGHSA enrichmentGHSA-336h-563m-gwm9 · GitHub severity CRITICAL · GitHub CVSS 9.1

Frequently asked(5)

What is CVE-2026-74521?
CVE-2026-74521 is a critical-severity vulnerability; its CVE record was published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: ksmbd: use memcmp() to compare ClientGUIDs ClientGUID is a fixed-size binary value and can contain embedded NUL bytes. strncmp() stops comparing at the first NUL byte, so different ClientGUID values can incorrectly be treated as…
When was the CVE record for CVE-2026-74521 published?
The CVE record for CVE-2026-74521 was published on August 15, 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 October 3, 2026; the record at its source may have been updated since.
Is CVE-2026-74521 actively exploited?
CVE-2026-74521 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-74521?
CVE-2026-74521 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-2026-74521?
A fix for CVE-2026-74521 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-74521 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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