Buffer Overflow Vulnerability in Tenda AC21 Router
CVE-2025-12611

8.7HIGH

Key Information:

Vendor

Tenda
Status
Ac21
Vendor
CVE Published:
3 November 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-12611?

A buffer overflow vulnerability exists in the Tenda AC21 router, specifically within the formSetPPTPServer function in the /goform/SetPptpServerCfg file. This flaw occurs due to improper handling of the startIp argument. By manipulating this parameter, an attacker could exploit the vulnerability remotely, potentially gaining unauthorized access to the system. Exploit code for this vulnerability is publicly available, increasing the urgency for affected users to apply necessary security measures.

Affected Version(s)

AC21 16.03.08.16

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-2025-12611 - Proof of Concept

References

https://vuldb.com/?id.330906
vdb-entrytechnical-description
https://vuldb.com/?ctiid.330906
signaturepermissions-required
https://vuldb.com/?submit.678491
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

LX-LX (VulDB User)
JSON
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CVE-2025-12611 : Buffer Overflow Vulnerability in Tenda AC21 Router