How severe is CVE-2026-21629?

CVE-2026-21629 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-21629 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21629?

CVE-2026-21629 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21629?

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

Does CVE-2026-21629 have an EU (EUVD) identifier?

Yes. CVE-2026-21629 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17853.

When was CVE-2026-21629 published?

CVE-2026-21629 was published on 2026-04-01 and last updated on 2026-06-17.

CVE-2026-21629

CVE-2026-21629 is a high-severity vulnerability in Joomla Joomla! with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: High (CVSS 3.x base score 7.3)
CVSS v4: 6.3
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-17853
Weakness: CWE-284
Affected product: Joomla Joomla!
Published: 2026-04-01
Last modified: 2026-06-17

Description

The ajax component was excluded from the default logged-in-user check in the administrative area. This behavior was potentially unexpected by 3rd party developers.

Frequently asked questions

What is CVE-2026-21629?: The ajax component was excluded from the default logged-in-user check in the administrative area. This behavior was potentially unexpected by 3rd party developers.
How severe is CVE-2026-21629?: CVE-2026-21629 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-21629 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21629?: CVE-2026-21629 affects Joomla Joomla!. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21629?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-21629 have an EU (EUVD) identifier?: Yes. CVE-2026-21629 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17853.
When was CVE-2026-21629 published?: CVE-2026-21629 was published on 2026-04-01 and last updated on 2026-06-17.

References

https://developer.joomla.org/security-centre/1027-20260301-core-acl-hardening-in-com-ajax.html

Affected products (1)

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

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