SB2021052539 - Multiple vulnerabilities in Joomla!

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Cross-site scripting (CVE-ID: CVE-2021-26032)

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 MediaHelper::canUpload. A remote attacker can inject 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.

2) Cross-site request forgery (CVE-ID: CVE-2021-26033)

The vulnerability allows a remote attacker to perform cross-site request forgery attacks.

The vulnerability exists due to insufficient validation of the HTTP request origin in AJAX reordering endpoint. A remote attacker can trick the victim to visit a specially crafted web page and perform arbitrary actions on behalf of the victim on the vulnerable website.

3) Cross-site request forgery (CVE-ID: CVE-2021-26034)

The vulnerability allows a remote attacker to perform cross-site request forgery attacks.

The vulnerability exists due to insufficient validation of the HTTP request origin within data download endpoints in com_banners and com_sysinfo components. A remote attacker can trick the victim to visit a specially crafted web page and perform arbitrary actions on behalf of the victim on the vulnerable website.

Remediation

Install update from vendor's website.

References

• https://developer.joomla.org/security-centre/852-20210501-core-adding-html-to-the-executable-block-list-of-mediahelper-canupload.html
• https://developer.joomla.org/security-centre/853-20210502-core-csrf-in-ajax-reordering-endpoint.html
• https://developer.joomla.org/security-centre/854-20210503-core-csrf-in-data-download-endpoints.html