Stack-Based Buffer Overflow in Tenda AC20 Router Firmware
CVE-2025-9791

8.7HIGH

Key Information:

Vendor

Tenda
Status
Ac20
Vendor
CVE Published:
1 September 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-9791?

A vulnerability has been discovered in the Tenda AC20 router firmware version 16.03.08.05, specifically in the /goform/fromAdvSetMacMtuWan file. This issue arises when the argument 'wanMTU' is improperly handled, leading to a stack-based buffer overflow. The vulnerability allows for potential remote exploitation, raising significant security concerns for users of this router model. Publicly available exploits further exacerbate the risk, making immediate awareness and action critical.

Affected Version(s)

AC20 16.03.08.05

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-2025-9791 - Proof of Concept

References

https://vuldb.com/?id.322106
vdb-entrytechnical-description
https://vuldb.com/?ctiid.322106
signaturepermissions-required
https://vuldb.com/?submit.641088
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

BediveRE (VulDB User)
.