Which versions of Vigor300b Firmware are affected by CVE-2026-3040?

Organizations using DrayTek Vigor 300B should be aware of moderate risk from CVE-2026-3040, a command injection vulnerability rated CVSS 4.7.

Is there a public PoC exploit available for CVE-2026-3040?

Yes, a public proof-of-concept exploit is available for CVE-2026-3040. Prioritise patching immediately. EPSS: 0.3%.

Vigor300b Firmware CVE-2026-3040

Q: What is the CVSS score of CVE-2026-3040?

CVE-2026-3040 has a CVSS 4.0 base score of 2.0 (Low). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/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. EPSS exploitation probability: 0.3%.

LOW

Command Injection (CWE-77)

2026-02-23 cna@vuldb.com

Command Injection Vigor300b Firmware

2.0

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

2.0 LOW

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Lifecycle Timeline

Severity Changed

Apr 29, 2026 - 01:11 NVD

MEDIUM LOW

CVSS changed

Apr 29, 2026 - 01:11 NVD

4.7 (MEDIUM) 2.0 (LOW)

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

PoC Detected

Feb 26, 2026 - 16:11 vuln.today

Public exploit code

CVE Published

Feb 23, 2026 - 22:16 nvd

MEDIUM 4.7

DescriptionCVE.org

A vulnerability was identified in DrayTek Vigor 300B up to 1.5.1.6. This affects the function cgiGetFile of the file /cgi-bin/mainfunction.cgi/uploadlangs of the component Web Management Interface. The manipulation of the argument File leads to os command injection. The attack may be initiated remotely. The exploit is publicly available and might be used. The vendor confirms that "300B is EoL, and this is an authenticated vulnerability. We don't plan to fix it." This vulnerability only affects products that are no longer supported by the maintainer.

AnalysisAI

Command injection in DrayTek Vigor 300B firmware up to version 1.5.1.6 allows authenticated remote attackers to execute arbitrary OS commands via the File parameter in the web management interface. Public exploit code exists for this vulnerability, though the vendor has confirmed the product is end-of-life and no patch will be released. …

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Vulnerability AssessmentAI

Risk Assessment	CVSS 4.7 (MEDIUM). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	A remote attacker (requires authentication) could exploit this flaw, os command injection.
Remediation	Monitor vendor advisories for a patch. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 30 days: Identify affected systems running DrayTek Vigor 300B and apply vendor patches as part of regular patch cycle. …

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CVE-2026-3040 vulnerability details – vuln.today

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