CVE-2026-68388

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 2026-08-10. 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-2026-55574 (ENISA EUVD) · GHSA-h6fv-x4pg-r56c (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: 0.5%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: handle overlapping allocated ranges in fallocate

smb3_simple_fallocate_range() can skip holes when an allocated range returned by the server starts before the current fallocate offset. The skipped hole is not zero-filled, but fallocate still returns success. A later write to that hole may therefore fail with ENOSPC.

The function queries allocated ranges so that it can preserve existing contents and write zeroes only into holes. However, the server may return a range that starts before the current fallocate offset.

For example, assume the fallocate request is [100, 400) and the only allocated range returned by the server is [0, 200):

Request: [100, 400) Server range: [ 0, 200) allocated

Correct: [100, 200) allocated data, skip [200, 400) hole, zero-fill

Current: [100, 300) skipped [300, 400) zero-filled afterwards

The current code adds the full server range length, 200, to the current offset 100 and moves to 300. As a result, the hole in [200, 300) is skipped without being zero-filled.

Fix this by advancing only over the part of the allocated range that overlaps the current fallocate offset. Ignore ranges that end before the current offset and reject ranges whose end offset overflows.

This also prevents a malformed range length from causing an out-of-bounds zero-buffer read.

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.
Exploitation0.5% × 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
0.5%
EPSS %ILE
43rd
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
0.5% 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

August 10, 2026

Last Modified

October 19, 2026

Advisory Details (8)

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

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/f47c7277c03a636fcc3a57969f2dc09567b3c050
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b09ae45d85dc816987a71db9eebc54b0ae288e94
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/aeb58a4eb39a7ff4d7782b4f4ada0fda5e0675d2
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a4a09e5142835633fffbde68bd0a039ba4d4bf97
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7e08ab7a061b17ac1989a225c6afb53f44a86808
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/437637f5ff3f573b2edf8571de91fb00a21eb4e6
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/377fe3e583e46369ee1004d5cfe12271d6589a68
Web page

smb/client: handle overlapping allocated ranges in fallocate - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/01719883235507b1585e4c51e320d9a7113dc698

Patch Availability(19)

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 ... 6.1.99-1 (56 versions)
  • every version up to 6.1.187-1: fixed in 6.1.187-1
—
linux-6.126.12.100-1~deb12u1
  • every version up to 6.12.101-1~deb12u1: fixed in 6.12.101-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (32 versions)
  • every version up to 6.12.101-1: fixed in 6.12.101-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (161 versions)
  • every version up to 7.1.6-1: fixed in 7.1.6-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(15)

Data Freshness Timeline

(refreshed 28× in last 7d / 121× 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 595 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 495 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 03:11 UTCEG score recompute
  2. 2026-11-02 03:11 UTCVendor advisory
  3. 2026-11-02 03:11 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-11-01 00:50 UTCEG score recompute
  6. 2026-11-01 00:50 UTCVendor advisory
  7. 2026-11-01 00:50 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  9. 2026-10-30 22:29 UTCEG score recompute
  10. 2026-10-30 22:29 UTCVendor advisory
  11. 2026-10-30 22:29 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-10-29 20:08 UTCEG score recompute
  14. 2026-10-29 20:08 UTCVendor advisory
  15. 2026-10-29 20:08 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  17. 2026-10-28 17:48 UTCEG score recompute
  18. 2026-10-28 17:48 UTCVendor advisory
  19. 2026-10-28 17:47 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  22. 2026-10-27 15:25 UTCEG score recompute
  23. 2026-10-27 15:25 UTCVendor advisory
  24. 2026-10-27 15:25 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
Show 75 more
  1. 2026-10-26 12:43 UTCEG score recompute
  2. 2026-10-26 12:43 UTCVendor advisory
  3. 2026-10-26 12:43 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-10-25 14:10 UTCEG score recompute
  6. 2026-10-25 10:18 UTCEG score recompute
  7. 2026-10-25 10:18 UTCVendor advisory
  8. 2026-10-25 10:18 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  10. 2026-10-24 07:56 UTCEG score recompute
  11. 2026-10-24 07:56 UTCVendor advisory
  12. 2026-10-24 07:56 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  14. 2026-10-23 05:34 UTCEG score recompute
  15. 2026-10-23 05:34 UTCVendor advisory
  16. 2026-10-23 05:34 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  18. 2026-10-22 03:12 UTCEG score recompute
  19. 2026-10-22 03:12 UTCVendor advisory
  20. 2026-10-22 03:12 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  22. 2026-10-21 00:50 UTCEG score recompute
  23. 2026-10-21 00:50 UTCVendor advisory
  24. 2026-10-21 00:49 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  26. 2026-10-19 22:28 UTCEG score recompute
  27. 2026-10-19 22:28 UTCVendor advisory
  28. 2026-10-19 22:27 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  29. 2026-10-19 21:24 UTCEG score recompute
  30. 2026-10-19 21:24 UTCVendor advisory
  31. 2026-10-19 21:24 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  32. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  33. 2026-10-18 22:02 UTCEG score recompute
  34. 2026-10-18 22:02 UTCVendor advisory
  35. 2026-10-18 22:02 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  36. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  37. 2026-10-18 03:19 UTCEG score recompute
  38. 2026-10-17 19:07 UTCEG score recompute
  39. 2026-10-17 19:07 UTCVendor advisory
  40. 2026-10-17 19:06 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  41. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  42. 2026-10-16 16:45 UTCEG score recompute
  43. 2026-10-16 16:45 UTCVendor advisory
  44. 2026-10-16 16:44 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  46. 2026-10-16 16:04 UTCEG score recompute
  47. 2026-10-16 16:04 UTCVendor advisory
  48. 2026-10-16 16:04 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-10-15 16:42 UTCEG score recompute
  50. 2026-10-15 16:42 UTCVendor advisory
  51. 2026-10-15 16:42 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  53. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  54. 2026-10-14 10:45 UTCEG score recompute
  55. 2026-10-14 10:45 UTCVendor advisory
  56. 2026-10-14 10:44 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  58. 2026-10-13 08:21 UTCEG score recompute
  59. 2026-10-13 08:21 UTCVendor advisory
  60. 2026-10-13 08:20 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  62. 2026-10-12 15:45 UTCEG score recompute
  63. 2026-10-12 05:58 UTCVendor advisory
  64. 2026-10-12 05:58 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-10-11 19:30 UTCEG score recompute
  66. 2026-10-11 16:45 UTCEG score recompute
  67. 2026-10-11 14:06 UTCEG score recompute
  68. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  69. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  70. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  71. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  72. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  73. 2026-10-07 03:50 UTCVendor advisory
  74. 2026-10-07 03:50 UTCGHSA enrichmentGHSA-h6fv-x4pg-r56c · GitHub severity CRITICAL · GitHub CVSS 9.8
  75. 2026-10-06 23:07 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-68388?
CVE-2026-68388 is a critical-severity vulnerability; its CVE record was published on August 10, 2026. In the Linux kernel, the following vulnerability has been resolved: smb/client: handle overlapping allocated ranges in fallocate smb3_simple_fallocate_range() can skip holes when an allocated range returned by the server starts before the current fallocate offset. The skipped hole is not…
When was the CVE record for CVE-2026-68388 published?
The CVE record for CVE-2026-68388 was published on August 10, 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 19, 2026; the record at its source may have been updated since.
Is CVE-2026-68388 actively exploited?
CVE-2026-68388 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (43rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-68388?
CVE-2026-68388 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-2026-68388?
A fix for CVE-2026-68388 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-68388 are linked in the Vendor Advisories panel on this page.

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