Known exploited · DrayTek

CVE-2020-15415: DrayTek Multiple Vigor Routers OS Command Injection Vulnerability

What it is

DrayTek Vigor3900, Vigor2960, and Vigor300B devices contain an OS command injection vulnerability in cgi-bin/mainfunction.cgi/cvmcfgupload that allows for remote code execution via shell metacharacters in a filename when the text/x-python-script content type is used.

Added September 30, 2024Due October 21, 2024CISA KEV catalog 2026.10.01

Vendor: DrayTek
Product: Multiple Vigor Routers
Added to KEV: September 30, 2024
CISA due date: October 21, 2024
Ransomware use: Unknown
Weakness: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

What CISA requires

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Forensic triage

What to do now

Find every instance of Multiple Vigor Routers you run, including the forgotten ones, and check its version against the vendor advisory.
Apply the vendor's fix or mitigation, before October 21, 2024 if you are bound by CISA's deadline, sooner if it faces the internet.
Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops OS command injection payloads, including Shellshock.

References

CVE-2020-15415 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops OS command injection payloads, including Shellshock before they reach your application.

See the Dome

T Academy

Train the engineers who fix it

Security engineering on real hosts in the browser, every objective checked on the machine. The first two lessons of Linux 1 are free.

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.