How severe is CVE-2021-23128?

CVE-2021-23128 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-23128 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-23128?

CVE-2021-23128 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-23128?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-23128 published?

CVE-2021-23128 was published on 2021-03-04 and last updated on 2026-06-17.

CVE-2021-23128

CVE-2021-23128 is a critical-severity vulnerability in Joomla Joomla! with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Joomla Joomla!
Published: 2021-03-04
Last modified: 2026-06-17

Description

An issue was discovered in Joomla! 3.2.0 through 3.9.24. The core shipped but unused randval implementation within FOF (FOFEncryptRandval) used an potential insecure implemetation. That has now been replaced with a call to 'random_bytes()' and its backport that is shipped within random_compat.

Frequently asked questions

What is CVE-2021-23128?: An issue was discovered in Joomla! 3.2.0 through 3.9.24. The core shipped but unused randval implementation within FOF (FOFEncryptRandval) used an potential insecure implemetation. That has now been replaced with a call to 'random_bytes()' and its backport that is shipped within random_compat.
How severe is CVE-2021-23128?: CVE-2021-23128 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-23128 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-23128?: CVE-2021-23128 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-23128?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-23128 published?: CVE-2021-23128 was published on 2021-03-04 and last updated on 2026-06-17.

References

https://developer.joomla.org/security-centre/842-20210302-core-potential-insecure-fofencryptrandval.html

Affected products (1)

cpe:2.3:a:joomla:joomla\!:*:*:*:*:*:*:*:*

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