CVE-2021-26029Network attack vector

Author metadata overwrite via inadequate form filtering

Published Mar 4, 2021 · Updated Feb 25, 2026

Improper form filtering in Joomla! CMS 1.6.0 through 3.9.24 allows remote attackers to overwrite author metadata in core components. Form handling in com_fields, com_categories, com_banners, com_contact, com_newsfeeds, and com_tags persists inadequately filtered author-field values. No user interaction is required, and the reported consequence is limited to altering author attribution.

CVSS severity5.3
Medium
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper form filtering in Joomla! CMS 1.6.0 through 3.9.24 allows remote attackers to overwrite author metadata in core components. Form handling in com_fields, com_categories, com_banners, com_contact, com_newsfeeds, and com_tags persists inadequately filtered author-field values. No user interaction is required, and the reported consequence is limited to altering author attribution.

The record

CVE
CVE-2021-26029
Published
Mar 4, 2021
Updated
Feb 25, 2026
Vendor
Joomla! Project
Product
Joomla! CMS
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record 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=1.6.0-3.9.24

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Joomla! Project · Joomla! CMSversion=1.6.0-3.9.24

Published CVSS scores

5.0INCIBE-CERTAV:N/AC:L/Au:N/C:N/I:P/A:N
5.3INCIBE-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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.

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

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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