OS Command Injection Vulnerability in DrayTek Vigor 300B Web Management Interface
CVE-2026-3040

5.1MEDIUM

Key Information:

Vendor

Draytek
Status
Vigor 300b
Vendor
CVE Published:
23 February 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-3040?

A vulnerability exists in the DrayTek Vigor 300B's web management interface, specifically within the cgiGetFile function of the /cgi-bin/mainfunction.cgi/uploadlangs component. This security flaw allows for OS command injection through the manipulation of the File parameter, enabling remote attackers to execute arbitrary commands. The affected product version, 1.5.1.6, is no longer supported by DrayTek, which has confirmed it will not issue a patch for this vulnerability. As such, users should be aware of the risks associated with using this EoL product and take appropriate measures to secure their networks.

Affected Version(s)

Vigor 300B 1.5.1.0

Vigor 300B 1.5.1.1

Vigor 300B 1.5.1.2

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-2026-3040 - Proof of Concept

References

https://vuldb.com/?id.347394
vdb-entrytechnical-description
https://vuldb.com/?ctiid.347394
signaturepermissions-required
https://vuldb.com/?submit.757126
third-party-advisory

CVSS V4

Score:
5.1
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
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

jiefengliang (VulDB User)
.