CVE-2020-8515
CriticalExploitedPublic exploitDrayTek Vigor2960 1.3.1_Beta, Vigor3900 1.4.4_Beta, and Vigor300B 1.3.3_Beta, 1.4.2.1_Beta, and 1.4.4_Beta devices allow remote code execution as root (without authentication) via shell metacharacters to the cgi-bin/mainfunction.cgi URI.
Published Feb 1, 2020 · Updated Nov 7, 2025
Key Facts
Patch immediately- CVE-2020-8515 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Vigor2960 Firmware (Draytek), Vigor300b Firmware (Draytek), Vigor3900 Firmware (Draytek).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 3, 2020. Public exploit code is available.
- EPSS estimates a 100% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
100%
Higher than 99.9% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2020-8515 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
DrayTek Vigor2960 1.3.1_Beta, Vigor3900 1.4.4_Beta, and Vigor300B 1.3.3_Beta, 1.4.2.1_Beta, and 1.4.4_Beta devices allow remote code execution as root (without authentication) via shell metacharacters to the cgi-bin/mainfunction.cgi URI. This issue has been fixed in Vigor3900/2960/300B v1.5.1.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | May 3, 2022 | Not reported |
| Industry KEV feed | Apr 3, 2020 | May 3, 2022 | Not reported |
| CIRCL KEV | Nov 3, 2021 | May 3, 2022 | Not reported |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
5 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Vigor2960 FirmwareDraytek | 1.3.1-beta | n/a |
| Vigor300b FirmwareDraytek | 1.3.3-beta, 1.4.2.1-beta, 1.4.4-beta | n/a |
| Vigor3900 FirmwareDraytek | 1.4.4-beta | n/a |
Timeline
Publicly disclosed
Feb 1, 2020
Added to Industry KEV feed
Apr 3, 2020
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Nov 7, 2025
Weakness Type
- CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
References
- advisoryhttps://sku11army.blogspot.com/2020/01/draytek-unauthenticated-rce-in-draytek.html
- advisoryhttps://www.draytek.com/about/security-advisory/vigor3900-/-vigor2960-/-vigor300b-router-web-management-page-vulnerability-%28cve-2020-8515%29/
- exploithttp://packetstormsecurity.com/files/156979/DrayTek-Vigor2960-Vigor3900-Vigor300B-Remote-Command-Execution.html
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
DrayTek Vigor2960 1.3.1_Beta, Vigor3900 1.4.4_Beta, and Vigor300B 1.3.3_Beta, 1.4.2.1_Beta, and 1.4.4_Beta devices allow remote code execution as root (without authentication) via shell metacharacters to the cgi-bin/mainfunction.cgi URI.
Affected: Vigor2960 Firmware (Draytek) versions 1.3.1-beta; Vigor300b Firmware (Draytek) versions 1.3.3-beta, 1.4.2.1-beta, 1.4.4-beta; Vigor3900 Firmware (Draytek) versions 1.4.4-beta. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Apr 3, 2020.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of May 3, 2022.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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