SB2026040131 - Multiple vulnerabilities in Joomla!
Published: April 1, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 6 vulnerabilities.
1) Improper access control (CVE-ID: CVE-2026-21629)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions in com_ajax. A remote attacker can bypass implemented security restrictions and gain unauthorized access to the application.
2) Improper access control (CVE-ID: CVE-2026-23899)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions in webservice endpoints. A remote attacker can bypass implemented security restrictions and gain unauthorized access to the application.
3) External Control of File Name or Path (CVE-ID: CVE-2026-23898)
CWE-ID: CWE-73 - External Control of File Name or Path
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to delete arbitrary files.
The vulnerability exists due to application allows an attacker to control path of the files to delete in com_joomlaupdate. A remote attacker can delete arbitrary files on the system.
4) Cross-site scripting (CVE-ID: CVE-2026-21632)
CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data in various article title outputs. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
5) Cross-site scripting (CVE-ID: CVE-2026-21631)
CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data in com_associations comparison view. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
6) SQL injection (CVE-ID: CVE-2026-21630)
CWE-ID: CWE-89 - Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
The vulnerability allows a remote attacker to execute arbitrary SQL queries in database.
The vulnerability exists due to insufficient sanitization of user-supplied data in com_content articles webservice endpoint. A remote attacker can send a specially crafted request to the affected application and execute arbitrary SQL commands within the application database.
Successful exploitation of this vulnerability may allow a remote attacker to read, delete, modify data in database and gain complete control over the affected application.
Remediation
Install update from vendor's website.
References
- https://developer.joomla.org/security-centre/1027-20260301-core-acl-hardening-in-com-ajax.html
- https://developer.joomla.org/security-centre/1032-20260306-core-improper-access-check-in-webservice-endpoints.html
- https://developer.joomla.org/security-centre/1031-20260305-core-arbitrary-file-deletion-in-com-joomlaupdate.html
- https://developer.joomla.org/security-centre/1030-20260304-core-xss-vectors-in-various-article-title-outputs.html
- https://developer.joomla.org/security-centre/1029-20260303-core-xss-vector-in-com-associations-comparison-view.html
- https://developer.joomla.org/security-centre/1028-20260302-core-sql-injection-in-com-content-articles-webservice-endpoint.html