CVE-2019-3809
CRITICALCVE-2019-3809 is a critical-severity (CVSS 10) Cross-Site Request Forgery (CSRF) vulnerability in moodle/moodle. O3 Security confirms whether CVE-2019-3809 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Moodle Blind SSRF Risk in /badges/mybackpack.php
Blast Radius
moodle/moodleReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | moodle/moodle | ≥ 3.1&&< 3.1.16 | 3.1.16 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update moodle/moodle to 3.1.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-3809 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2019-3809 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2019-3809. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2019-3809 in your dependencies?
O3 detects CVE-2019-3809 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.