CVE-2023-35133 — moodle/moodle
HIGHCVE-2023-35133 is a high-severity (CVSS 7.5) Server-Side Request Forgery (SSRF) vulnerability in moodle/moodle. A fix is available for moodle/moodle — see the affected versions and patch details below.
Moodle: ssrf risk due to insufficient check on the curl blocked hosts
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-35133.
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-2023-35133 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 378,156 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/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
An issue in the logic used to check 0.0.0.0 against the cURL blocked hosts lists resulted in an SSRF risk. This flaw affects Moodle versions 4.2, 4.1 to 4.1.3, 4.0 to 4.0.8, 3.11 to 3.11.14, 3.9 to 3.9.21 and earlier unsupported versions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | moodle/moodle | ≥ 4.2.0&&< 4.2.1 | 4.2.1composer require moodle/moodle:^4.2.1 |
| 🐘Packagist | moodle/moodle | ≥ 4.1.0&&< 4.1.4 | 4.1.4composer require moodle/moodle:^4.1.4 |
| 🐘Packagist | moodle/moodle | ≥ 4.0.0&&< 4.0.9 | 4.0.9composer require moodle/moodle:^4.0.9 |
| 🐘Packagist | moodle/moodle | ≥ 3.10.0&&< 3.11.15 | 3.11.15composer require moodle/moodle:^3.11.15 |
| 🐘Packagist | moodle/moodle | all versions | 3.9.22composer require moodle/moodle:^3.9.22 |
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 4.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-35133 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-2023-35133 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-35133. 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-2023-35133 in your dependencies?
O3 Security finds CVE-2023-35133 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.