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01 Record

CVE-2026-6688

FatFs Buffer Overflow via Unbounded LFN Filename Copy

HighPUBLISHEDCNA: runZero
CNA base score7.6 CVSS v3.xCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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02 Description

FatFs Buffer Overflow via Unbounded LFN Filename Copy

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.32% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 25.0% of scored records. A rank, not a probability.
NVD base score
7.6 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD analysis status
Analyzed. NVD last modified this record on 2026-10-25.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-07-01 14:01Z4 MO AGO
Last updated
2026-07-01 15:06Z4 MO AGO
Reserved
2026-04-20
Assigning CNA
runZero
Record state
PUBLISHED
Severity
High (CVSS 7.6)
CNA CVSS vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Weaknesses
  • CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')Base
Data version
5.2
Document digest
ea262a0b7df3a7e13e1ff46218e5a89794a1bb6f4b2fca411ca0700f66ab7786

05 Affected products

VendorProductVersionsPlatforms
ChaNFatFs0 to R0.16—

06 References