CVE-2023-37260 is a high-severity (CVSS 8.2) CWE-209 vulnerability in league/oauth2-server. A fix is available for league/oauth2-server — see the affected versions and patch details below.
league/oauth2-server key exposed in exception message when passing as string and providing invalid pass phrase
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.
- 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-2023-37260.
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-2023-37260 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 377,333 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
league/oauth2-server🐘league/oauth2-serverReal-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
league/oauth2-server is an implementation of an OAuth 2.0 authorization server written in PHP. Starting in version 8.3.2 and prior to version 8.5.3, servers that passed their keys to the CryptKey constructor as as string instead of a file path will have had that key included in a LogicException message if they did not provide a valid pass phrase for the key where required. This issue has been patched so that the provided key is no longer exposed in the exception message in the scenario outlined above. Users should upgrade to version 8.5.3 to receive the patch. As a workaround, pass the key as a file instead of a string.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | league/oauth2-server | ≥ 8.3.2&&< 8.4.2 | 8.4.2composer require league/oauth2-server:^8.4.2 |
| 🐘Packagist | league/oauth2-server | ≥ 8.5.0&&< 8.5.3 | 8.5.3composer require league/oauth2-server:^8.5.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for league/oauth2-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update league/oauth2-server to 8.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37260 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-2023-37260 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-37260. 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-2023-37260 in your dependencies?
O3 Security finds CVE-2023-37260 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.