MAC Filtering Vulnerability in TOTOLINK A720R Product
CVE-2026-82539

9.4CRITICAL

Key Information:

Vendor

Totolink
Status
A720r
Vendor
CVE Published:
30 August 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-82539?

A vulnerability exists in the TOTOLINK A720R router due to improper handling of the 'desc' argument in the MAC Filtering functionality within the cstecgi.cgi file. This flaw can be exploited remotely, allowing attackers to manipulate memory and potentially execute malicious code. The vulnerability has been publicly disclosed, and affected users should apply appropriate security measures to mitigate the risks associated with potential exploitation.

Affected Version(s)

A720R 4.1.5cu.630_B20250509

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-2026-82539 - Proof of Concept

References

https://vuldb.com/vuln/397055
vdb-entrytechnical-description
https://vuldb.com/vuln/397055/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-82539
third-party-advisory

CVSS V4

Score:
9.4
Severity:
CRITICAL
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

Nicola Giuffrida
Xernary (VulDB User)
Xernary (VulDB User)
.