RCE in Draytek Vigor 300b

CVE-2026-3040

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.

Vulnerability class: Command Injection (OS Command Injection)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.072 (94.1th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 94.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-3040: fell from 0.088 to 0.072.

EPSS over last 30 days · oldest: 0.088 · newest: 0.072 · change: -0.016

Affected products

Weakness classification (CWE)

References

  • vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
  • vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry, Third Party Advisory)
  • vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
  • github.com/master-abc/cve/issues/42 (issue-tracking, Exploit, exploit, Issue Tracking)

Frequently asked questions

What is CVE-2026-3040?
CVE-2026-3040 is a medium-severity vulnerability in Draytek Vigor 300b, classified under Command Injection. CVSS score: 4.7/10. Published 2026-02-23.
How severe is CVE-2026-3040?
Medium severity. CVSS v3 base score is 4.7 out of 10.