Buffer Overflow Vulnerability in Tenda AC20 Wireless Router
CVE-2025-8939

8.7HIGH

Key Information:

Vendor

Tenda
Status
Ac20
Vendor
CVE Published:
14 August 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-8939?

A buffer overflow flaw has been discovered in the Tenda AC20 wireless router, specifically within the /goform/WifiGuestSet file. The issue arises from improper handling of the shareSpeed argument, allowing attackers to exploit this vulnerability remotely. This can potentially lead to unauthorized access or system compromise. As the exploit has been made public, users are encouraged to take preventive measures to secure their devices.

Affected Version(s)

AC20 16.03.08.0

AC20 16.03.08.1

AC20 16.03.08.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2025-8939 - Proof of Concept

References

https://vuldb.com/?id.319902
vdb-entrytechnical-description
https://vuldb.com/?ctiid.319902
signaturepermissions-required
https://vuldb.com/?submit.631829
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

QMSSDXN (VulDB User)
.
CVE-2025-8939 : Buffer Overflow Vulnerability in Tenda AC20 Wireless Router