FatFs R0.16 and earlier contains a divide-by-zero in exFAT sync logic bug when crafted metadata causes n_fatent - 2 to be zero during write/sync operations. This maps to CWE-369 (Divide By Zero). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (4.6, Medium). Network-delivered update media can make this remote in some pipelines. The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
CVE-2026-6683
Score 4.6 from GitHub Security Advisory published 2026-07-01. a secondary CVSS source baseline 4.6; sources differ by 0.0.
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 4.6
- EG Score
- 4.6(high)
- EPSS
- 10.6%
- KEV
- Not listed
Published
July 1, 2026
Last Modified
July 2, 2026
Advisory Details (3)
Auto-updated Jul 3, 2026GitHub - runZeroInc/vulns-2026-fatfs-chance · GitHub
https://github.com/runZeroInc/vulns-2026-fatfs-chanceSeven FatFs bugs, one very large blast radius
https://www.runzero.com/blog/fatfs-bugs/FatFs exFAT divide-by-zero in sync/write paths
https://www.runzero.com/advisories/fatfs-exfat-divide-by-zero-cve-2026-6683Vendor Advisories for CVE-2026-6683(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 18× in last 7d / 18× 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.
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 14:19 UTCEG score recompute
- 2026-07-06 14:19 UTCGHSA enrichment
- 2026-07-05 14:39 UTCEG score recompute
- 2026-07-05 14:38 UTCGHSA enrichment
- 2026-07-05 02:31 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 14:58 UTCEG score recompute
- 2026-07-04 14:58 UTCGHSA enrichment
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-03 15:20 UTCEG score recompute
- 2026-07-03 15:20 UTCGHSA enrichment
- 2026-07-02 15:41 UTCEG score recompute
- 2026-07-02 15:41 UTCGHSA enrichment
- 2026-07-01 16:03 UTCEG score recompute
- 2026-07-01 16:03 UTCGHSA enrichment
Related CVEs(same CWE)
Frequently asked(5)
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-6683
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