CVE-2018-1081 — moodle/moodle
MEDIUMCVE-2018-1081 is a medium-severity (CVSS 5.3) Cross-site Scripting (XSS) vulnerability in moodle/moodle. A fix is available for moodle/moodle — see the affected versions and patch details below.
Moodle Unauthenticated users can trigger custom messages to admin via paypal enrol script
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2018-1081 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
moodle/moodle🐘moodle/moodle🐘moodle/moodle🐘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 3.4 to 3.4.1, 3.3 to 3.3.4, 3.2 to 3.2.7, 3.1 to 3.1.10 and earlier unsupported versions. Unauthenticated users can trigger custom messages to admin via paypal enrol script. Paypal IPN callback script should only send error emails to admin after request origin was verified, otherwise admin email can be spammed.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | moodle/moodle | ≥ 3.1&&< 3.1.11 | 3.1.11composer require moodle/moodle:^3.1.11 |
| 🐘Packagist | moodle/moodle | ≥ 3.2&&< 3.2.8 | 3.2.8composer require moodle/moodle:^3.2.8 |
| 🐘Packagist | moodle/moodle | ≥ 3.3&&< 3.3.5 | 3.3.5composer require moodle/moodle:^3.3.5 |
| 🐘Packagist | moodle/moodle | ≥ 3.4&&< 3.4.2 | 3.4.2composer require moodle/moodle:^3.4.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for moodle/moodle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update moodle/moodle to 3.1.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1081 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2018-1081 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-1081. 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-2018-1081 in your dependencies?
O3 Security finds CVE-2018-1081 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.