CVE-2021-20128Public exploitNetwork attack vector

Stored script execution via unsanitized profile names

Published Oct 13, 2021 · Updated Aug 3, 2024

Stored cross-site scripting in DrayTek VigorConnect 1.6.0-B3 allows remote authenticated users to run scripts in another user's browser. The Floor Plan handler stores the Profile Name without adequate sanitization and later renders the supplied markup in the Network Menu page. Administrative access is required to submit the payload, and another user's page view triggers access to browser-session data and actions available to that user.

CVSS severity3.5
Low
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in DrayTek VigorConnect 1.6.0-B3 allows remote authenticated users to run scripts in another user's browser. The Floor Plan handler stores the Profile Name without adequate sanitization and later renders the supplied markup in the Network Menu page. Administrative access is required to submit the payload, and another user's page view triggers access to browser-session data and actions available to that user.

The record

CVE
CVE-2021-20128
Published
Oct 13, 2021
Updated
Aug 3, 2024
Vendor
DrayTek
Product
VigorConnect
Classifications
CWE-79, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=1.6.0-B3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

DrayTek · VigorConnectversion=1.6.0-B3

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
3.5TenableCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

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

Technologies

Your stack

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Your stack

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