ChaN FatFs up to R0.16 f_getlabel stack-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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4.3$0-$5k0.66

Summaryinfo

A vulnerability classified as critical has been found in ChaN FatFs up to R0.16. Affected by this issue is the function f_getlabel. The manipulation leads to stack-based overflow. This vulnerability is listed as CVE-2026-6687. It is possible to launch the attack on the physical device. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, has been found in ChaN FatFs up to R0.16. This issue affects the function f_getlabel. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was presented by Hd Moore. It is possible to read the advisory at runzero.com. The identification of this vulnerability is CVE-2026-6687 since 04/20/2026. The exploitation is known to be easy. Attacking locally is a requirement. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-40999). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Yes
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/20/2026 CVE reserved
07/01/2026 +72 days Advisory disclosed
07/01/2026 +0 days VulDB entry created
07/01/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: runzero.com
Researcher: Hd Moore
Status: Not defined

CVE: CVE-2026-6687 (🔒)
GCVE (CVE): GCVE-0-2026-6687
GCVE (VulDB): GCVE-100-375563
EUVD: 🔒

Entryinfo

Created: 07/01/2026 17:19
Updated: 07/01/2026 19:09
Changes: 07/01/2026 17:19 (54), 07/01/2026 19:09 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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