CVE-2026-123959

TOTOLINK CA300-PoE cstecgi.cgi setLanguageCfg buffer overflow

9.4 Critical

A security flaw has been discovered in TOTOLINK CA300-PoE 6.2c.884. The impacted element is the function setLanguageCfg of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument langType results in buffer overflow. The attack can be initiated remotely. The exploit has been released to the public and may be used for attacks.

Attack profile

How easy it is to exploit

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

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.84%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 setLanguageCfg buffer overflow

Record: CVE-2026-123959
CVSS 4.0: 9.4 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C
CVSS 3.0: 9.1 CriticalCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C
CVSS 2.0: 8.3 AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:C
Weakness: CWE-120, CWE-119
Updated: 2026-11-07

EUVDEUVD-2026-119111 9.4

Record: EUVD-2026-119111
CVSS 4.0: 9.4 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
Updated: 2026-11-07

GitHub AdvisoriesGHSA-8359-43qx-xvjr 8.5

A security flaw has been discovered in TOTOLINK CA300-PoE 6.2c.884. The impacted element is the...

Record: GHSA-8359-43qx-xvjr
CVSS 4.0: 8.5 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:H/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: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weakness: CWE-119
Updated: 2026-11-07

NVD 8.5

Record: CVE-2026-123959
CVSS 4.0: 8.5 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:H/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: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS 2.0: 8.3 HighAV:N/AC:L/Au:M/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
Nov 7, 2026	published	EUVD
Nov 7, 2026	aliases, references	GitHub Advisories, NVD
Nov 7, 2026	aliases, published	EUVD
Nov 7, 2026	first indexed	CVE List

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

In short

CVE-2026-123959 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 0.84%, the 58th percentile. No source names a fixed version.