CVE-2021-20124Known exploitationPublic exploitNetwork attack vector

Unauthenticated file disclosure via WebServlet traversal

Published Oct 13, 2021 · Updated Oct 21, 2025

Path traversal in DrayTek VigorConnect 1.6.0-B3 allows remote attackers to read arbitrary operating-system files via the WebServlet download endpoint. The WebServlet getMapImg_acs2 handler accepts directory-traversal filename values and returns files such as /etc/passwd or win.ini with root privileges. No authentication is required, so any network-reachable VigorConnect service can suffer confidentiality loss without reported integrity or availability impact.

CVSS severity7.5
High
EPSS probability96.31%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in DrayTek VigorConnect 1.6.0-B3 allows remote attackers to read arbitrary operating-system files via the WebServlet download endpoint. The WebServlet getMapImg_acs2 handler accepts directory-traversal filename values and returns files such as /etc/passwd or win.ini with root privileges. No authentication is required, so any network-reachable VigorConnect service can suffer confidentiality loss without reported integrity or availability impact.

The record

CVE
CVE-2021-20124
Published
Oct 13, 2021
Updated
Oct 21, 2025
Vendor
DrayTek
Product
VigorConnect
Classifications
CWE-22, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.6.0
  2. Affected versionversion=1.6.0-B3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

DrayTek · VigorConnectversion=1.6.0; version=1.6.0-B3

Published CVSS scores

7.5TenableCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.

Daily unique IPsShadowserver observations through Sep 16, 2026. Gaps indicate unavailable data.
Sep 10, 2026Sep 16, 2026
View daily counts
Reporting dayUnique IPs
Sep 10, 20261
Sep 11, 2026Unavailable
Sep 12, 2026Unavailable
Sep 13, 2026Unavailable
Sep 14, 20261
Sep 15, 20261
Sep 16, 20261
Latest reporting daySep 16, 2026
Latest daily unique IPs1
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System

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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