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Fencer Intel
critical 9.8

CVE-2020-8515 kev in the critical feed json

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 execut…

published 6y ago modified 4mo ago also EUVD-2020-29381

cvss
9.8
version 3.1, CNA
cisa kev
Exploited
added 2021-11-03
epss
100.0%
EPSS 100.0% chance of exploitation in 30 days, percentile 99.9%
public exploits
1
Exploit-DB, plus a Nuclei check

Summary

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.

Patch / fix

cisa required action Apply updates per vendor instructions.

Is CVE-2020-8515 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Timeline

  1. Published
  2. First public exploit (EDB-48268)
  3. Added to CISA KEV
  4. CISA patch deadline
  5. CISA SSVC: exploitation active

Known exploited

Added
5y ago
Patch by
2022-05-03 (4y ago)
Ransomware
Not known
Required action
Apply updates per vendor instructions.
Vendor, product
DrayTek, Multiple Vigor Routers
CISA name
Multiple DrayTek Vigor Routers Web Management Page Vulnerability

ATT&CK techniques

How it is exploited and what it leads to, in MITRE ATT&CK terms.

  • T1133 External Remote Services exploitation
  • T1059 Command and Scripting Interpreter primary impact
  • T1496 Resource Hijacking secondary impact

kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
total
Assessed
last yr.

Exploit prediction

99.99% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-48268 Multiple DrayTek Products - Pre-authentication Remote Root Code Execution remote, 2020-03-30
  • Nuclei template DrayTek - Remote Code Execution nuclei detection template
  • packetstormsecurity.com http://packetstormsecurity.com/files/156979/DrayTek-Vigor2960-Vigor3900-Vigor300B-Remote-Command-Execution.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.