FatFs prior to R0.16 that use GPT scanning with 'FF_LBA64 = 1' contains an issue where an unbounded loop count derived from GPT header field GPTH_PtNum, enabling extremely long or effectively infinite mount-time scans. This maps to CWE-835 (Loop with Unreachable Exit Condition). 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). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 4.6 · elm-chanNVD modified 2026-10-25 17:10
Affected (CPE criteria) 1
cpe:2.3:a:elm-chan:fatfs:*:*:*:*:*:*:*:*
References 5
- https://elm-chan.org/fsw/ff/ Product
- https://github.com/runZeroInc/vulns-2026-fatfs-chance Third Party Advisory, Exploit
- https://www.runzero.com/advisories/fatfs-gpt-scan-loop-dos-cve-2026-6684/ Third Party Advisory
- https://www.runzero.com/blog/fatfs-bugs/ Third Party Advisory, Exploit
- https://github.com/runZeroInc/vulns-2026-fatfs-chance Third Party Advisory, Exploit