CVE-2021-40973Network attack vector

Arbitrary script injection via installer lastname parameter

Published Oct 1, 2021 · Updated Aug 4, 2024

Cross-site scripting in Spotweb 1.5.1 and earlier allows remote attackers to inject arbitrary web script or HTML through the installer lastname parameter. The templates/installer/step-004.inc.php installer template accepts attacker-controlled lastname input and places it into generated HTML, allowing script markup to execute in a victim browser. Exploitation requires a remote attacker to induce user interaction with the affected installer flow; impact is limited to browser-side confidentiality and integrity changes described by the published assessment.

CVSS severity6.1
Medium
EPSS probability2.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Spotweb 1.5.1 and earlier allows remote attackers to inject arbitrary web script or HTML through the installer lastname parameter. The templates/installer/step-004.inc.php installer template accepts attacker-controlled lastname input and places it into generated HTML, allowing script markup to execute in a victim browser. Exploitation requires a remote attacker to induce user interaction with the affected installer flow; impact is limited to browser-side confidentiality and integrity changes described by the published assessment.

The record

CVE
CVE-2021-40973
Published
Oct 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

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

6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NVDAV:N/AC:M/Au:N/C:N/I:P/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 IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

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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