CVE-2020-15415
RCE in Draytek Vigor3900 Firmware ≤ 1.5.1
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2020-15415 is a critical-severity OS Command Injection (CWE-78) vulnerability in Draytek Vigor3900 Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique NTDS (T1003.003); ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2020-15415 is an OS command injection vulnerability (CWE-78) affecting DrayTek Vigor3900, Vigor2960, and Vigor300B devices running firmware prior to 1.5.1. The flaw resides in the cgi-bin/mainfunction.cgi/cvmcfgupload endpoint, which fails to sanitize filenames containing shell metacharacters when the Content-Type header is set to text/x-python-script. This issue is distinct from the related CVE-2020-14472.
Unauthenticated attackers with network access can exploit the vulnerability by sending a crafted HTTP request that triggers arbitrary command execution on the device. Successful exploitation grants full control over the affected appliance, allowing attackers to read or modify data, alter device configuration, or disrupt availability, consistent with the CVSS 9.8 rating reflecting no required privileges or user interaction.
DrayTek's security advisory recommends upgrading to firmware version 1.5.1 or later to remediate the flaw. The vulnerability is also tracked in CISA's Known Exploited Vulnerabilities catalog, and public proof-of-concept material is available from the CLP-team repository documenting the command-injection technique.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-7408
Vulnerability Data
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.
- CWE(s)
- KEV Date Added
- 30 September 2024
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.5V1.2.8
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.
Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.