CVE-2026-102586 Moodle: xss via password reset link due to insufficient username escaping

What is CVE-2026-102586?

CVE-2026-102586 is a medium-severity cross-site scripting vulnerability in Moodle Moodle, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

A flaw was found in Moodle. Insufficient sanitization of username input on the password reset page allows a remote attacker to conduct a cross-site scripting (XSS) attack. By convincing an unauthenticated user to access a specially crafted password reset link, an attacker could execute arbitrary script in the victim's browser.

Weakness: CWE-79

Which versions are affected by CVE-2026-102586?

1 open source package ship an affected version, including moodle. It affects 1 product.

Products include Moodle Moodle.

How do I fix CVE-2026-102586?

Upgrade moodle to a fixed version for your release line: 4.5.13, 5.0.9, 5.1.6 or 5.2.2.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-102586 being exploited?

There is no known exploitation of CVE-2026-102586 in the wild and no public exploit code.

Other vulnerabilities in Moodle Moodle

• CVE-2006-4935 File upload in n/a Critical 10.0
• CVE-2006-4936 Moodle does not properly validate module instance id Critical 10.0
• CVE-2004-2233 Unknown "front page vulnerability with Moodle servers" for Moodle before 1.3.2 has unknown impact and attack vectors. Critical 10.0
• CVE-2004-2235 Cross-site scripting in n/a Critical 10.0
• CVE-2004-2236 Other in n/a Critical 10.0

All Moodle Moodle vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-moodle-2026-102586, GHSA-rfv4-mv3r-qx66, UBUNTU-CVE-2026-102586.