CVE-2020-8515Known exploitationPublic exploitNetwork attack vector

Unauthenticated root code execution via keyPath injection

Published Feb 1, 2020 · Updated Oct 21, 2025

Command injection in affected DrayTek Vigor2960, Vigor3900, and Vigor300B firmware allows remote attackers to execute code as root. The /www/cgi-bin/mainfunction.cgi executable fails to filter the keyPath parameter, allowing encoded quote and newline characters to bypass authentication checks and introduce shell commands. No authentication is required; a network request to an exposed WebUI grants complete root-level control of the router.

CVSS severity9.8
Critical
EPSS probability99.99%
Next 30 days · Nov 1, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in affected DrayTek Vigor2960, Vigor3900, and Vigor300B firmware allows remote attackers to execute code as root. The /www/cgi-bin/mainfunction.cgi executable fails to filter the keyPath parameter, allowing encoded quote and newline characters to bypass authentication checks and introduce shell commands. No authentication is required; a network request to an exposed WebUI grants complete root-level control of the router.

The record

CVE
CVE-2020-8515
Published
Feb 1, 2020
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-78, T1059.004, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 1, 2020CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2020Exploitation reportedHoaxcalls botnet propagation through CVE-2020-8515
  3. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsShadowserver observations through Sep 28, 2026. Gaps indicate unavailable data.
Sep 22, 2026Sep 28, 2026
View daily counts
Reporting dayUnique IPs
Sep 22, 20268
Sep 23, 20263
Sep 24, 202611
Sep 25, 202617
Sep 26, 20266
Sep 27, 202616
Sep 28, 20268
Latest reporting daySep 28, 2026
Latest daily unique IPs8
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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