How severe is CVE-2026-6684?

CVE-2026-6684 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-6684 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6684?

CVE-2026-6684 affects Elm-chan Fatfs. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-6684?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-6684 published?

CVE-2026-6684 was published on 2026-07-01 and last updated on 2026-07-02.

CVE-2026-6684

CVE-2026-6684 is a medium-severity vulnerability in Elm-chan Fatfs with a CVSS 3.x base score of 4.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-835.

Key facts

Severity: Medium (CVSS 3.x base score 4.6)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-835
Affected product: Elm-chan Fatfs
Published: 2026-07-01
Last modified: 2026-07-02

Description

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.

Frequently asked questions

What is CVE-2026-6684?: 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.
How severe is CVE-2026-6684?: CVE-2026-6684 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-6684 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6684?: CVE-2026-6684 affects Elm-chan Fatfs. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-6684?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-6684 published?: CVE-2026-6684 was published on 2026-07-01 and last updated on 2026-07-02.

References

Affected products (1)

cpe:2.3:a:elm-chan:fatfs:*:*:*:*:*:*:*:*

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