CVE-2026-3040 DrayTek Vigor 300B Web Management uploadlangs cgiGetFile os command injection
Authenticated attackers can execute arbitrary OS commands via the web management interface of the end-of-life DrayTek Vigor 300B router.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-3040?
CVE-2026-3040 is a medium-severity command injection vulnerability in DrayTek Vigor 300B, published on 23 Feb 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-3040?
It affects 1 product.
Products include Draytek Vigor300b Firmware.
How do I fix CVE-2026-3040?
No fix has been published for CVE-2026-3040 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-3040 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3040 exists.
Sources
Also known as GHSA-9xx2-jmjv-w5vp.