Moodle HQ up to 4.5.12/5.0.8/5.1.5/5.2.1 Output templates cross site scripting

Summaryinfo

A vulnerability was found in Moodle HQ Moodle up to 4.5.12/5.0.8/5.1.5/5.2.1. It has been declared as problematic. The affected element is an unknown function of the file templates of the component Output. Such manipulation leads to cross site scripting. This vulnerability is documented as CVE-2026-102581. The attack can be executed remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Moodle HQ Moodle up to 4.5.12/5.0.8/5.1.5/5.2.1. It has been rated as problematic. Affected by this issue is some unknown processing of the file templates of the component Output. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. CVE summarizes:

A flaw was found in Moodle. Insufficient output escaping in templates used to display forum posts enables a stored cross-site scripting (XSS) vulnerability. An attacker can inject malicious content into a forum post, which then executes arbitrary script code in the browser of another user viewing the affected post.

The advisory is shared for download at git.moodle.org. This vulnerability is handled as CVE-2026-102581 since 09/29/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/30/2026). The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 4.5.13, 5.0.9, 5.1.6 or 5.2.2 eliminates this vulnerability.

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Productinfo

Type

• Learning Management Software

Vendor

• Moodle HQ

Name

• Moodle

Version

• 4.5.0
• 4.5.1
• 4.5.2
• 4.5.3
• 4.5.4
• 4.5.5
• 4.5.6
• 4.5.7
• 4.5.8
• 4.5.9
• 4.5.10
• 4.5.11
• 4.5.12
• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.0.7
• 5.0.8
• 5.1.0
• 5.1.1
• 5.1.2
• 5.1.3
• 5.1.4
• 5.1.5
• 5.2.0
• 5.2.1

License

• open-source

CPE 2.3info

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CPE 2.2info

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