How severe is CVE-2021-23127?

CVE-2021-23127 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-2021-23127 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-2021-23127?

CVE-2021-23127 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-23127?

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-2021-23127 published?

CVE-2021-23127 was published on 2021-03-04 and last updated on 2026-06-17.

CVE-2021-23127

CVE-2021-23127 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. Usage of an insufficient length for the 2FA secret accoring to RFC 4226 of 10 bytes vs 20 bytes.

Frequently asked questions

What is CVE-2021-23127?: An issue was discovered in Joomla! 3.2.0 through 3.9.24. Usage of an insufficient length for the 2FA secret accoring to RFC 4226 of 10 bytes vs 20 bytes.
How severe is CVE-2021-23127?: CVE-2021-23127 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-2021-23127 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-2021-23127?: CVE-2021-23127 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-23127?: 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-2021-23127 published?: CVE-2021-23127 was published on 2021-03-04 and last updated on 2026-06-17.

References

https://developer.joomla.org/security-centre/841-20210301-core-insecure-randomness-within-2fa-secret-generation.html

Affected products (1)

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

More vulnerabilities in Joomla Joomla!

CVE-2026-48904 — Critical (CVSS 9.8): An improper access check allows privelege escalation through the com_users group editing webservice endpoint.
CVE-2026-48902 — Critical (CVSS 9.8): The password and username reset features created plain http links for https connections if the "Force SSL" flag wasn't…
CVE-2026-48899 — Critical (CVSS 9.8): An improper access check allows privilege escalation through the com_users batch task.
CVE-2026-48898 — Critical (CVSS 9.8): An improper access check allows privilege escalation through the com_users batch task.
CVE-2026-40383 — Critical (CVSS 9.8): An improper validation of user-supplied input leads to a local file inclusion vulnerability.
CVE-2026-35223 — Critical (CVSS 9.8): An improper access check allows unauthorized access to com_config webservice endpoints.

All CVEs affecting Joomla Joomla! →