CVE-2026-6688

HIGHPre-NVD 7.67.6—
EchelonGraph scoreMEDIUM confidence

Score 7.6 from GitHub Security Advisory (severity: HIGH) published 2026-07-01. a secondary CVSS source baseline 7.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.6Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy without Checking Size of Input). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.

CVSS v3
7.6
EG Score
7.6(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity76% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
25%
KEV
Not listed

Published

July 1, 2026

Last Modified

July 2, 2026

Advisory Details (3)

Auto-updated Jul 2, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic

GitHub - runZeroInc/vulns-2026-fatfs-chance · GitHub

https://github.com/runZeroInc/vulns-2026-fatfs-chance
generic🔴 Active Exploitation

Seven FatFs bugs, one very large blast radius

https://www.runzero.com/blog/fatfs-bugs/
generic🔴 Active Exploitation

FatFS long filename overflow in downstream callers

https://www.runzero.com/advisories/fatfs-long-fn-of-downstream-cve-2026-6688/

Vendor Advisories for CVE-2026-6688(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 71× 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 204 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-6688?
CVE-2026-6688 is a high vulnerability published on July 1, 2026. FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename handling. With LFN enabled, fno.fname can be up to 255 characters; many callers copy it into short fixed buffers without bounds checks, causing overflow. This maps to CWE-120 (Buffer Copy…
When was CVE-2026-6688 disclosed?
CVE-2026-6688 was first published in the National Vulnerability Database on July 1, 2026, with the most recent update on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6688 actively exploited?
CVE-2026-6688 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 75.0% of all scored CVEs.
What is the CVSS score of CVE-2026-6688?
CVE-2026-6688 has a CVSS v3 base score of 7.6 (NVD).
How do I remediate CVE-2026-6688?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6688, 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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