What is CVE-2019-3809?

CVE-2019-3809 is a medium-severity vulnerability in Moodle, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2019-03-25.

How severe is CVE-2019-3809?

Medium severity. CVSS v3 base score is 6.5 out of 10.

CSRF in Moodle

CVE-2019-3809

A flaw was found in Moodle versions 3.1 to 3.1.15 and earlier unsupported versions. The mybackpack functionality allowed setting the URL of badges, when it should be restricted to the Mozilla Open Badges backpack URL. This resulted in the possibility of blind SSRF via requests made by the page.

Vulnerability class: CSRF (Cross-Site Request Forgery)

Published 2019-03-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.

EPSS exploit prediction

EPSS: 0.009 (57.1th percentile), scored 2026-10-06.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 57.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Moodle
[Unknown] Moodle — versions 3.1.16

Weakness classification (CWE)

References

bugzilla.redhat.com/show_bug.cgi (Patch, Third Party Advisory, Issue Tracking)
moodle.org/mod/forum/discuss.php (Patch, Vendor Advisory)
git.moodle.org/gw (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2019-3809?: CVE-2019-3809 is a medium-severity vulnerability in Moodle, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2019-03-25.
How severe is CVE-2019-3809?: Medium severity. CVSS v3 base score is 6.5 out of 10.