Vulnerability · Published Aug 14, 2026 · Assigned by VulDB

CVE-2026-19811TOTOLINK A800R firewall.so cstecgi.cgi setIpQosRules stack-based overflow

High 8.8

In plain English

A high-severity stack buffer overflow in A800R from TOTOLINK. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 58% of all known vulnerabilities).

Severity (CVSS 3.1)8.8High

Exploit odds (30 days)0.9%top 41.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

A security flaw has been discovered in TOTOLINK A800R 4.1.2cu.5137_B20200730. The impacted element is the function setIpQosRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so. The manipulation of the argument Comment results in stack-based buffer overflow. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks.

Affected products (as reported)

Vendor	Product	Versions
TOTOLINK	A800R	4.1.2cu.5137_B20200730

Weakness: CWE-121, CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R

References

VDB-389947 | TOTOLINK A800R firewall.so cstecgi.cgi setIpQosRules stack-based overflow vdb-entry, technical-description
VDB-389947 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
CVE-2026-19811 | CVE Analysis and Report third-party-advisory
Submit #869425 | Totolink A800R V4.1.2cu.5137_B20200730 Buffer Overflow third-party-advisory
https://github.com/panda666-888/vuls/blob/main/totolink/a800r/setIpQosRules.md exploit
https://www.totolink.net/ product