What’s Vulnerable › Vulnerabilities

CVE-2026-102581: Moodle: xss in forum post templates due to insufficient escaping

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-30 · updated 2026-10-01
• Weakness: CWE-79

Description

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.

Affected products

• Moodle: before 4.5.13; from 5.0.0 before 5.0.9; from 5.1.0 before 5.1.6; from 5.2.0 before 5.2.2 — fixed in 4.5.13, 5.0.9, 5.1.6, 5.2.2

How to fix

Upgrade to a fixed version: Moodle 4.5.13, 5.0.9, 5.1.6, 5.2.2. Check the vendor advisory for mitigations.

References

• http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-88981
• https://access.redhat.com/security/cve/CVE-2026-102581
• https://bugzilla.redhat.com/show_bug.cgi?id=2543634
• https://moodle.org/mod/forum/discuss.php?d=482499

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