CVE-2026-64136

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-19. A secondary CVSS source baseline 9.8; 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

Also known asEUVD-2026-45821 (ENISA EUVD) · GHSA-6vvf-f9vp-vcgv (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked()

Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes.

There was missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked().

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 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.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
34th
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 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 2026-11-01). 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; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

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

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). 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 19, 2026

Last Modified

October 30, 2026

Advisory Details (6)

Auto-updated Oct 30, 2026
Patch available.
Web page

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e374f4e496fef8168784f93a4477d67be34485fd
Web page

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bf4ebdb19ff9b3cdf992b50715fe61633327416a
Web page

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7df1df6f40c0720d30206aa35c0343b962350e0d
Web page

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7585d4242f59185b084957fa077396e53dbf7c24
Web page

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4d8690dace005a38e6dbde9ecce2da3ad85c7c41
Web page

smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/13fb413ae22a37c69341918a6d651d19a9b0b9b7

Patch Availability(22)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-nvidia-hwe-26.04 (7.0.0-2016.16) @ resolute2026-11-01ubuntu
ubuntulinux-virtual-6.8 (6.8.0-139.139) @ noble2026-11-01ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1036.37) @ noble2026-11-01ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1061.64) @ noble2026-11-01ubuntu
ubuntulinux-tools-lowlatency-hwe-20.04-edge (6.8.0-139.139.1) @ noble2026-11-01ubuntu
ubuntulinux-tools-oracle-edge (7.0.0-1011.11~24.04.1) @ noble2026-11-01ubuntu
ubuntulinux-tools-aws-lts-24.04 (6.8.0-1064.67) @ noble2026-11-01ubuntu
ubuntulinux-tools-ibm-edge (6.8.0-1066.67~22.04.1) @ jammy2026-11-01ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2053.55) @ noble2026-11-01ubuntu
ubuntulinux-tools-raspi-realtime-7.0 (7.0.0-1015.15) @ resolute2026-11-01ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1067.75+fips1) @ noble2026-11-01ubuntu
ubuntulinux-tools-oracle-7.0 (7.0.0-1008.8) @ resolute2026-11-01ubuntu
ubuntulinux-tools-azure-fde-7.0 (7.0.0-1009.9) @ resolute2026-11-01ubuntu
ubuntulinux-tools-gcp-edge (7.0.0-1011.11~24.04.1) @ noble2026-11-01ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1067.75) @ noble2026-11-01ubuntu
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1035.38) @ noble2026-11-01ubuntu
ubuntulinux-tools-azure-edge (6.8.0-1067.75~22.04.1) @ jammy2026-11-01ubuntu
ubuntulinux-tools-azure-edge (7.0.0-1014.14~24.04.1) @ noble2026-11-01ubuntu
ubuntulinux-tools-aws-fips-6.8 (6.8.0-1064.67+fips1) @ noble2026-11-01ubuntu
ubuntulinux-tools-nvidia-hwe-24.04-edge (7.0.0-1016.16) @ resolute2026-11-01ubuntu
redhatkernel-0:5.14.0-687.45.1.el9_82026-09-08redhat
redhatkernel-0:6.12.0-211.50.1.el10_22026-09-01redhat

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

(2 across 2 ecosystems)
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.38-1 ... 6.12.94-1~bpo12+1 (27 versions)
  • every version up to 6.12.94-1: fixed in 6.12.94-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (142 versions)
  • every version up to 7.0.12-1: fixed in 7.0.12-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(20)

Data Freshness Timeline

(refreshed 29× in last 7d / 104× 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 646 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 546 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 17:52 UTCEG score recompute
  2. 2026-11-01 17:52 UTCVendor advisory
  3. 2026-11-01 17:51 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  5. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  6. 2026-10-31 15:39 UTCEG score recompute
  7. 2026-10-31 15:39 UTCVendor advisory
  8. 2026-10-31 15:39 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  10. 2026-10-30 13:28 UTCEG score recompute
  11. 2026-10-30 13:28 UTCVendor advisory
  12. 2026-10-30 13:27 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-30 12:42 UTCEG score recompute
  14. 2026-10-30 12:42 UTCVendor advisory
  15. 2026-10-30 12:41 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-29 18:00 UTCEG score recompute
  17. 2026-10-29 18:00 UTCVendor advisory
  18. 2026-10-29 18:00 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  19. 2026-10-29 17:59 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  21. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  22. 2026-10-28 15:44 UTCEG score recompute
  23. 2026-10-28 15:44 UTCVendor advisory
  24. 2026-10-28 15:44 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
Show 75 more
  1. 2026-10-27 13:32 UTCEG score recompute
  2. 2026-10-27 13:32 UTCVendor advisory
  3. 2026-10-27 13:31 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-10-26 10:51 UTCEG score recompute
  6. 2026-10-26 10:51 UTCVendor advisory
  7. 2026-10-26 10:51 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  9. 2026-10-25 14:12 UTCEG score recompute
  10. 2026-10-25 08:39 UTCEG score recompute
  11. 2026-10-25 08:39 UTCVendor advisory
  12. 2026-10-25 08:39 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  14. 2026-10-24 06:26 UTCEG score recompute
  15. 2026-10-24 06:26 UTCVendor advisory
  16. 2026-10-24 06:26 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  18. 2026-10-23 04:12 UTCEG score recompute
  19. 2026-10-23 04:12 UTCVendor advisory
  20. 2026-10-23 04:12 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  22. 2026-10-22 01:58 UTCEG score recompute
  23. 2026-10-22 01:58 UTCVendor advisory
  24. 2026-10-22 01:58 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  26. 2026-10-20 23:44 UTCEG score recompute
  27. 2026-10-20 23:43 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  29. 2026-10-19 21:29 UTCEG score recompute
  30. 2026-10-19 21:29 UTCVendor advisory
  31. 2026-10-19 21:29 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  32. 2026-10-19 20:34 UTCEG score recompute
  33. 2026-10-19 20:34 UTCVendor advisory
  34. 2026-10-19 20:34 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  35. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  36. 2026-10-18 21:11 UTCEG score recompute
  37. 2026-10-18 21:11 UTCVendor advisory
  38. 2026-10-18 21:10 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  40. 2026-10-18 03:23 UTCEG score recompute
  41. 2026-10-17 18:57 UTCEG score recompute
  42. 2026-10-17 18:57 UTCVendor advisory
  43. 2026-10-17 18:56 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  44. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  45. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  46. 2026-10-16 16:41 UTCEG score recompute
  47. 2026-10-16 16:41 UTCVendor advisory
  48. 2026-10-16 16:40 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-10-16 15:49 UTCEG score recompute
  50. 2026-10-16 15:49 UTCVendor advisory
  51. 2026-10-16 15:49 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-10-15 16:40 UTCEG score recompute
  53. 2026-10-15 16:40 UTCVendor advisory
  54. 2026-10-15 16:40 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  56. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  57. 2026-10-14 10:41 UTCEG score recompute
  58. 2026-10-14 10:41 UTCVendor advisory
  59. 2026-10-14 10:40 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  61. 2026-10-13 08:23 UTCEG score recompute
  62. 2026-10-13 08:23 UTCVendor advisory
  63. 2026-10-13 08:22 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  65. 2026-10-12 15:48 UTCEG score recompute
  66. 2026-10-12 06:10 UTCVendor advisory
  67. 2026-10-12 06:09 UTCGHSA enrichmentGHSA-6vvf-f9vp-vcgv · GitHub severity CRITICAL · GitHub CVSS 9.8
  68. 2026-10-11 19:32 UTCEG score recompute
  69. 2026-10-11 16:48 UTCEG score recompute
  70. 2026-10-11 14:09 UTCEG score recompute
  71. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  72. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  73. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  74. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  75. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile

Frequently asked(5)

What is CVE-2026-64136?
CVE-2026-64136 is a critical-severity vulnerability; its CVE record was published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes.…
When was the CVE record for CVE-2026-64136 published?
The CVE record for CVE-2026-64136 was published on July 19, 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 30, 2026; the record at its source may have been updated since.
Is CVE-2026-64136 actively exploited?
CVE-2026-64136 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (34th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-64136?
CVE-2026-64136 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-64136?
A fix for CVE-2026-64136 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-64136 are linked in the Vendor Advisories panel on this page.

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