CVE-2020-15415
On DrayTek Vigor3900, Vigor2960, and Vigor300B devices before 1.5.1, cgi-bin/mainfunction.cgi/cvmcfgupload allows remote command execution via shell metacharacters in a filename when the text/x-python-script content type is used, a different issue than CVE-2020-14472.
do firstApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? Partly. The attack is delivered via an HTTP POST request to a specific CGI endpoint with a special content type and a filename containing shell metacharacters, which is unusual and can be detected by a WAF rule. A WAF rule can match POST to cgi-bin/mainfunction.cgi/cvmcfgupload with Content-Type text/x-python-script and filename containing shell metacharacters. No tracked WAF vendor has published a rule for this CVE yet, so you would write it yourself.
What a custom rule would match: POST to cgi-bin/mainfunction.cgi/cvmcfgupload with Content-Type text/x-python-script and filename containing shell metacharacters
Also consider: patch · custom WAF rule · shlex/execve-style APIs
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2020-15415 being exploited?
Yes. CVE-2020-15415 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2020-15415?
CVE-2020-15415 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2020-15415?
Yes. A fix has been recorded for CVE-2020-15415. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2020-15415 affect?
CVE-2020-15415 affects draytek:vigor3900_firmware, draytek:vigor2960_firmware, draytek:vigor300b_firmware. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
public exploits
Detection templates only, no public exploit found: 1 Nuclei template
- DrayTek Vigor - Command Injection · detection template · critical
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- active
- automatable
- yes
- technical impact
- total
Assessed by CISA 4 Oct 2024 (SSVC 2.0.3).
timeline
- 30 Jun 2020Published
- 30 Sept 2024Added to CISA KEV (exploited in the wild) · 1,552 days (about 4 years) later
- 4 Oct 2024CISA SSVC assessment: exploitation active · 5 days later
- 21 Oct 2024CISA remediation due date (US federal agencies) · 16 days later
- 21 Oct 2025CVE record last updated · 366 days (about 1 year) later
- 2 Nov 2026Analysed by vulneraibility.com · 377 days (about 1 year) later
- Linkdraytek.com /about/security-advisory
- Linkgithub.com /CLP-team/Vigor-Commond-Injection
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-15415
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Nuclei templates: detection templates
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.