CVE-2021-23131Network attack vector

Service interruption via invalid template manager input

Published Mar 4, 2021 · Updated Feb 25, 2026

Improper input validation in Joomla! CMS 3.2.0 through 3.9.24 allows remote attackers to interrupt service via template manager input. Joomla has not published the affected request parameter, validation error, or code path within the template manager. The public record identifies no authentication or configuration gate and bounds the reported consequence to service interruption, without data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Joomla! CMS 3.2.0 through 3.9.24 allows remote attackers to interrupt service via template manager input. Joomla has not published the affected request parameter, validation error, or code path within the template manager. The public record identifies no authentication or configuration gate and bounds the reported consequence to service interruption, without data disclosure or modification.

The record

CVE
CVE-2021-23131
Published
Mar 4, 2021
Updated
Feb 25, 2026
Vendor
Joomla! Project
Product
Joomla! CMS
Classifications
CWE-20, T1499
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=3.2.0-3.9.24

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Joomla! Project · Joomla! CMSversion=3.2.0-3.9.24

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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-20Improper Input Validation
T1499Endpoint Denial of Service

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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