Vulnerability · Published Aug 30, 2026 · Assigned by VulDB

CVE-2026-82539TOTOLINK A720R MAC Filtering cstecgi.cgi setMacFilterRules memory corruption

Critical 9.1

In plain English

A critical-severity memory corruption in A720R from TOTOLINK. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 58% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 3.1)9.1Critical

Exploit odds (30 days)0.8%top 42.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack tooling1Public PoC

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
TOTOLINK	A720R	4.1.5cu.630_B20250509

Weakness: CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R

References

VDB-397055 | TOTOLINK A720R MAC Filtering cstecgi.cgi setMacFilterRules memory corruption vdb-entry, technical-description
VDB-397055 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
CVE-2026-82539 | CVE Analysis and Report third-party-advisory
Submit #888696 | TOTOLINK A720R V4.1.5cu.630_B20250509 Buffer Overflow third-party-advisory
https://github.com/Xernary/CVE-2026-82539 exploit
https://www.totolink.net/ product