CVE-2021-42946Public exploitNetwork attack vector

Stored script execution via unescaped Copyright field

Published Mar 31, 2022 · Updated Aug 4, 2024

Stored XSS in HTMLy 2.8.1 allows remote authenticated users to execute script through the Copyright field on /admin/config. The saved Copyright value is rendered inside a span without neutralizing markup, so a payload can close the element and add an event-bearing body element. Administrator access is required to change the setting, and another user must interact with a page that renders the poisoned value.

CVSS severity4.8
Medium
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in HTMLy 2.8.1 allows remote authenticated users to execute script through the Copyright field on /admin/config. The saved Copyright value is rendered inside a span without neutralizing markup, so a payload can close the element and add an event-bearing body element. Administrator access is required to change the setting, and another user must interact with a page that renders the poisoned value.

The record

CVE
CVE-2021-42946
Published
Mar 31, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 31, 2022CVE 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

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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