Vulnerability · Published Nov 7, 2026 · Assigned by VulDB
CVE-2026-123957TOTOLINK CA300-PoE cstecgi.cgi setIpQosRules buffer overflow
Critical 9.9
In plain English
A critical-severity buffer overflow in CA300-PoE from TOTOLINK. There are no confirmed reports of exploitation so far.
Severity (CVSS 3.1)9.9Critical
Exploit odds (30 days)–no EPSS score yet
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
A vulnerability was determined in TOTOLINK CA300-PoE 6.2c.884. Impacted is the function setIpQosRules of the file /cgi-bin/cstecgi.cgi. This manipulation of the argument ipStart causes buffer overflow. It is possible to initiate the attack remotely. The exploit has been publicly disclosed and may be utilized.
Affected products (as reported)
Weakness: CWE-120, CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C
References
- VDB-432020 | TOTOLINK CA300-PoE cstecgi.cgi setIpQosRules buffer overflow vdb-entry, technical-description
- VDB-432020 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
- CVE-2026-123957 | CVE Analysis and Report third-party-advisory
- Submit #1033672 | TOTOLINK CA300-PoE CA300-PoE_Firmware V6.2c.884 Buffer Overflow third-party-advisory
- https://lavender-bicycle-a5a.notion.site/TOTOLINK-CA300-PoE-setIpQosRules-3f953a41781f801195e5e07dfe7488b9?source=copy_link exploit
- https://www.totolink.net/ product