CVE-2021-23128

Weak random values via insecure FOF generator

Published Mar 4, 2021 · Updated Feb 25, 2026

Insecure randomness in FOFEncryptRandval in Joomla! CMS 3.2.0 through 3.9.24 allows attackers an unspecified impact. The bundled but unused FOF implementation generates randval output with a potentially insecure routine rather than random_bytes(). Joomla states that core does not call this implementation, so no reachable security consequence is documented in a default installation.

CVSS severity9.1
Critical
EPSS probability1.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure randomness in FOFEncryptRandval in Joomla! CMS 3.2.0 through 3.9.24 allows attackers an unspecified impact. The bundled but unused FOF implementation generates randval output with a potentially insecure routine rather than random_bytes(). Joomla states that core does not call this implementation, so no reachable security consequence is documented in a default installation.

The record

CVE
CVE-2021-23128
Published
Mar 4, 2021
Updated
Feb 25, 2026
Vendor
Joomla! Project
Product
Joomla! CMS
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Joomla! Project · Joomla! CMSversion=3.2.0-3.9.24

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:N
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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