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High CVSS 7.6

CVE-2026-6687

Elm-chan Fatfs

FatFs R0.16 and earlier contains a stack overflow bug in f_getlabel() because exFAT label length (XDIR_NumLabel) is trusted without enforcing spec maximums. This maps to CWE-121 (Stack-based Buffer Overflow). Estimated CVSS v3.1 vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (7.6, High). The estimated CISA SSVC vectors are Exploitation: PoC, Technical Impact: Total.

What this means

Exposure
Exploitable with physical access to the device, without authentication and with no action from the victim.
Impact
An attacker can read sensitive data, modify or destroy data and take the service offline. The impact spreads beyond the vulnerable component into other parts of the system.
Weakness
A stack overflow overwrites the return address, which often leads to code execution.
Likelihood
Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.

What to doFold into the next patch cycle.

Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.

Published
1 July 2026
CVSS
7.6 (v3.1) CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS
0.46% probability of exploitation within 30 days · above 37% of all CVEs
Weakness
CWE-121
Sources
nvd
References

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