Buffer Overflow Vulnerability in TOTOLINK CA300-PoE Product
CVE-2026-123959

9.4CRITICAL

Key Information:

Vendor

Totolink
Status
Ca300-poe
Vendor
CVE Published:
7 November 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-123959?

A significant security flaw has been identified in the TOTOLINK CA300-PoE product, specifically within the function setLanguageCfg located in /cgi-bin/cstecgi.cgi. This vulnerability occurs when an attacker manipulates the langType argument, resulting in a buffer overflow that can be exploited remotely. The exploit details have been publicly disclosed, making this an urgent issue for users of the affected product. It is crucial for users to apply necessary patches or mitigations to safeguard against potential attacks.

Affected Version(s)

CA300-PoE 6.2c.884

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-123959 - Proof of Concept

References

https://vuldb.com/vuln/432022
vdb-entrytechnical-description
https://vuldb.com/vuln/432022/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-123959
third-party-advisory

CVSS V4

Score:
9.4
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

wxhwxhwxh_mie (VulDB User)
.