CVE-2024-51251: Draytek Vigor3900 · OS Command Injection
Source CVE Database V5
Not known to be exploited · CVSS 8.0 High.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Nov 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
- Immediately restrict access to the Draytek Vigor3900 management interface to trusted IP addresses only, preferably via VPN or secure management networks.
- Implement strict network segmentation to isolate management interfaces from general user networks and the internet.
- Monitor network traffic for unusual requests to mainfunction.cgi, especially those invoking the backup function, and set up alerts for suspicious command injection patterns.
- Disable or limit the backup function if possible until a vendor patch is available.
- Regularly audit router configurations and logs for signs of compromise or unauthorized changes.
- Engage with Draytek support to obtain firmware updates or patches addressing this vulnerability as soon as they are released.
- Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting command injection attempts on Draytek devices.
- Educate network administrators on this vulnerability and enforce strong authentication and access policies for device management.
Description
In Draytek Vigor3900 1.5.1.3, attackers can inject malicious commands into mainfunction.cgi and execute arbitrary commands by calling the backup function.