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8.5

CVE-2026-82539: TOTOLINK A720R router can be remotely crashed via MAC filter

CVE-2026-82539 · published 4 days ago
Summary

The A720R router’s MAC‑filtering feature can be tricked by sending a specially crafted request, causing the device’s memory to become corrupted. This can make the router stop working or become unstable, and it can be done from outside the network. Update the router firmware or disable the MAC‑filtering function until a fix is applied.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
VendorProductAffected versions
totolink a720r 4.1.5cu.630_B20250509
Original advisory text
A vulnerability was determined in TOTOLINK A720R 4.1.5cu.630_B20250509. This impacts the function setMacFilterRules of the file cstecgi.cgi of the component MAC Filtering. Executing a manipulation ...
A vulnerability was determined in TOTOLINK A720R 4.1.5cu.630_B20250509. This impacts the function setMacFilterRules of the file cstecgi.cgi of the component MAC Filtering. Executing a manipulation of the argument desc can lead to memory corruption. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized.
References
Severity
8.5 High
CVSS 3.1: 9.1 (MITRE)
Exploitation
EPSS <1%
Type
CWE-119Buffer Overflow
Timeline
Published30 Aug 2026
Updated1 Sep 2026
First seen30 Aug 2026
Sources
CVE-2026-82539 · MITRE
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