CVE-2018-6520 — simplesamlphp
MEDIUMCVE-2018-6520 is a medium-severity (CVSS 6.1) Open Redirect vulnerability in simplesamlphp/simplesamlphp. A fix is available for simplesamlphp/simplesamlphp — see the affected versions and patch details below.
SimpleSAMLphp Open redirection protection bypass
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
simplesamlphp/simplesamlphpReal-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
SimpleSAMLphp before 1.15.2 allows remote attackers to bypass an open redirect protection mechanism via crafted authority data in a URL.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | simplesamlphp/simplesamlphp | all versions | 1.15.2composer require simplesamlphp/simplesamlphp:^1.15.2 |
Affected Products
simplesamlphpsimplesamlphpDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for simplesamlphp/simplesamlphp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update simplesamlphp/simplesamlphp to 1.15.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-6520 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.
Frequently Asked Questions
Is CVE-2018-6520 in your dependencies?
Find it across Packagist, including transitive dependencies.