How severe is CVE-2026-6683?

CVE-2026-6683 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-2026-6683 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-2026-6683?

CVE-2026-6683 affects Elm-chan Fatfs. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-6683?

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

When was CVE-2026-6683 published?

CVE-2026-6683 was published on 2026-07-01 and last updated on 2026-07-02.

CVE-2026-6683

CVE-2026-6683 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-369.

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-369
Affected product: Elm-chan Fatfs
Published: 2026-07-01
Last modified: 2026-07-02

Description

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.

Frequently asked questions

What is CVE-2026-6683?: 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.
How severe is CVE-2026-6683?: CVE-2026-6683 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-2026-6683 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-2026-6683?: CVE-2026-6683 affects Elm-chan Fatfs. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-6683?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-6683 published?: CVE-2026-6683 was published on 2026-07-01 and last updated on 2026-07-02.

References

Affected products (1)

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

More vulnerabilities in Elm-chan Fatfs

CVE-2026-6688 — High (CVSS 7.6): FatFs R0.16 and earlier contains a downstream-caller vulnerability pattern associated with FatFs long filename…
CVE-2026-6687 — High (CVSS 7.6): FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is…
CVE-2026-6682 — High (CVSS 7.6): In FatFS R0.16 and earlier contains a FAT32 integer overflow bug in mount_volume() where fasize *= fs->n_fats can wrap,…
CVE-2026-6685 — Medium (CVSS 6.1): FatFs R0.16 and earlier exhibits a stale dirty-cache skip via unsigned-subtraction wrap in f_read() / f_write()…
CVE-2026-6686 — Medium (CVSS 4.6): FatFs R0.16 and earlier contains an uninitialized cluster exposure when f_lseek() extends files beyond EOF without…
CVE-2026-6684 — Medium (CVSS 4.6): FatFs prior to R0.16 that use GPT scanning with 'FF_LBA64 = 1' contains an issue where an unbounded loop count derived…

All CVEs affecting Elm-chan Fatfs →

Other CWE-369 (Divide By Zero) vulnerabilities

CVE-2021-32494 — Critical (CVSS 10.0): Radare2 has a division by zero vulnerability in Mach-O parser's rebase_buffer function. This allow attackers to create…
CVE-2017-11720 — Critical (CVSS 9.8): There is a division-by-zero vulnerability in LAME 3.99.5, caused by a malformed input file.
CVE-2020-20892 — High (CVSS 8.8): An issue was discovered in function filter_frame in libavfilter/vf_lenscorrection.c in Ffmpeg 4.2.1, allows attackers…
CVE-2025-4637 — High (CVSS 8.7): Divide By Zero vulnerability in davisking dlib allows remote attackers to cause a denial of service via a crafted…
CVE-2026-37232 — High (CVSS 8.6): An issue was discovered in OpenAirInterface5G 2.4.0 (nr-softmodem) in the E2SM-KPM RAN Function's PRB utilization…
CVE-2024-26945 — High (CVSS 8.4): In the Linux kernel, the following vulnerability has been resolved: crypto: iaa - Fix nr_cpus < nr_iaa case If…

Browse all CWE-369 (Divide By Zero) vulnerabilities →