What is GHSA-h94p-vjqx-v7rr?

GHSA-h94p-vjqx-v7rr is a security advisory published by GitHub Security Advisories with Medium severity. FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files...

Which CVE IDs does GHSA-h94p-vjqx-v7rr cover?

GHSA-h94p-vjqx-v7rr covers the following CVE IDs: CVE-2026-6686. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-h94p-vjqx-v7rr?

GHSA-h94p-vjqx-v7rr has a CVSS v3 base score of 4.6, published by GitHub Security Advisories.

GHSA-h94p-vjqx-v7rrMediumCVSS 4.6

FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files...

Vendor

GitHub Security Advisories

Published

July 1, 2026

Last Modified

July 1, 2026

🔗 CVE IDs covered (1)

CVE-2026-6686 →

📋 Description

FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without zero-filling newly allocated clusters. This maps to CWE-908 (Use of Uninitialized Resource). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (4.6, Medium). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Partial.

🔗 References (6)

https://nvd.nist.gov/vuln/detail/CVE-2026-6686
https://elm-chan.org/fsw/ff
https://github.com/runZeroInc/vulns-2026-fatfs-chance
https://www.runzero.com/advisories/fatfs-uninit-cluster-exposure-cve-2026-6686
https://www.runzero.com/blog/fatfs-bugs
https://github.com/advisories/GHSA-h94p-vjqx-v7rr