CVE-2026-123957

TOTOLINK CA300-PoE cstecgi.cgi setIpQosRules buffer overflow

9.4 Critical

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.47%Scored on 2026-11-07. The trend appears after a second daily score.

What each source reports

CVE List Score used 9.4

TOTOLINK CA300-PoE cstecgi.cgi setIpQosRules buffer overflow

Record: CVE-2026-123957
CVSS 4.0: 9.4 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
CVSS 3.1: 9.9 CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C
CVSS 3.0: 9.9 CriticalCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C
CVSS 2.0: 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:C
Weakness: CWE-120, CWE-119
Updated: 2026-11-07

EUVDEUVD-2026-118996 9.4

Record: EUVD-2026-118996
CVSS 4.0: 9.4 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
Updated: 2026-11-07

GitHub AdvisoriesGHSA-wxh7-x4wq-j3rp 8.6

A vulnerability was determined in TOTOLINK CA300-PoE 6.2c.884. Impacted is the function...

Record: GHSA-wxh7-x4wq-j3rp
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 9.9 CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weakness: CWE-119
Updated: 2026-11-07

NVD 8.6

Record: CVE-2026-123957
CVSS 4.0: 8.6 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 9.9 CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS 2.0: 9.0 HighAV:N/AC:L/Au:S/C:C/I:C/A:C
Weakness: CWE-119, CWE-120
Updated: 2026-11-07

Affected products

totolink ca300-poe

History

History
Recorded	Changed	Sources
Nov 7, 2026	published	EUVD, NVD
Nov 7, 2026	published	EUVD
Nov 7, 2026	aliases, references	GitHub Advisories
Nov 7, 2026	cwes, references, severity, title	CVE List
Nov 7, 2026	first indexed	EUVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-123957 is a critical vulnerability (CVSS 9.4) in Totolink Ca300-poe, published November 7, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.47%, the 40th percentile. No source names a fixed version.