Unauthorized access-level changes via insufficient API ACL
Published Sep 29, 2026 · Updated Sep 29, 2026
Improper access control in Joomla! CMS 4.0.0 through 5.4.8 and 6.0.0 through 6.1.3 lets remote authenticated users mutate access levels. The access-level webservice endpoints apply an insufficient ACL check before accepting mutation actions; the vendor has not identified the exact handler or missing permission test. Exploitation requires high-privilege credentials, and the published description does not establish which access levels can be changed or what further access results.
Summary
What happened
Improper access control in Joomla! CMS 4.0.0 through 5.4.8 and 6.0.0 through 6.1.3 lets remote authenticated users mutate access levels. The access-level webservice endpoints apply an insufficient ACL check before accepting mutation actions; the vendor has not identified the exact handler or missing permission test. Exploitation requires high-privilege credentials, and the published description does not establish which access levels can be changed or what further access results.
The record
- CVE
- CVE-2026-90913
- Published
- Sep 29, 2026
- Updated
- Sep 29, 2026
- Vendor
- Joomla! Project
- Product
- Joomla! CMS
- Classifications
- CWE-284
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Sep 29, 2026CVE publishedPublication date reported by the CVE source.
- Sep 29, 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.
- Affected versionversion=4.0.0-5.4.8
- Affected versionversion=6.0.0-6.1.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
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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