Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-6687— FatFs Stack Buffer Overflow via Uncapped exFAT Label Length

Quick assessment

Affected
ChaN FatFs
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

ChaN FatFs是ChaN公司的一个为嵌入式系统设计的通用 FAT/exFAT 文件系统模块。 ChaN FatFs R0.16及之前版本存在缓冲区错误漏洞，该漏洞源于在f_getlabel()函数中信任exFAT标签长度而未强制实施规范最大值，可能导致栈缓冲区溢出。

CVSS 7.6 · High EPSS 0.35% · P26

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 1

VendorProduct Version RangeStatus
ChaN FatFs ≤ R0.16 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-6687

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
FatFs Stack Buffer Overflow via Uncapped exFAT Label Length
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
栈缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
ChaN FatFs 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
ChaN FatFs是ChaN公司的一个为嵌入式系统设计的通用 FAT/exFAT 文件系统模块。 ChaN FatFs R0.16及之前版本存在缓冲区错误漏洞，该漏洞源于在f_getlabel()函数中信任exFAT标签长度而未强制实施规范最大值，可能导致栈缓冲区溢出。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
ChaN FatFs 0 ~ R0.16 -

II. Public POCs for CVE-2026-6687

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 8397 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-6687

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-6687 (1)

Security Blog Posts for CVE-2026-6687 (1)

Vendor Pages for CVE-2026-6687 (1)

Other References for CVE-2026-6687 (1)

Same Patch Batch · ChaN · 2026-07-01 · 6 CVEs total

CVE-2026-6688 7.6 HIGH FatFs Buffer Overflow via Unbounded LFN Filename Copy
CVE-2026-6682 7.6 HIGH FatFs Integer Overflow in FAT32 Volume Mount
CVE-2026-6684 4.6 MEDIUM FatFs Infinite Loop in GPT Partition Scan
CVE-2026-6686 4.6 MEDIUM FatFs Use of Uninitialized Clusters After Seek Past EOF
CVE-2026-6683 4.6 MEDIUM FatFs Divide-by-Zero in exFAT Sync

IV. Related Vulnerabilities

Same product: FatFs
Same vendor: ChaN
Same weakness: CWE-121

V. Comments for CVE-2026-6687

No comments yet

Leave a comment