Buffer Overflow Vulnerability in Tenda AC20 Router
CVE-2025-8940

8.7HIGH

Key Information:

Vendor

Tenda
Status
Ac20
Vendor
CVE Published:
14 August 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-8940?

A serious buffer overflow vulnerability exists in the Tenda AC20 router within the strcpy function located in /goform/saveParentControlInfo. By manipulating the argument 'Time', unauthorized remote attackers can exploit this flaw to execute arbitrary code. As the exploit has been made public, it poses significant risks to users still operating vulnerable versions of the device, encouraging immediate review and remediation.

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-2025-8940 - Proof of Concept

References

https://vuldb.com/?id.319903
vdb-entrytechnical-description
https://vuldb.com/?ctiid.319903
signaturepermissions-required
https://vuldb.com/?submit.631836
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-2025-8940 : Buffer Overflow Vulnerability in Tenda AC20 Router