GHSA-cvrm-5hp6-h523 is a medium-severity (CVSS 4.7) Open Redirect vulnerability in simplesamlphp/simplesamlphp-module-casserver. O3 Security confirms whether GHSA-cvrm-5hp6-h523 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
SimpleSAMLphp casserver: Open Redirect in logout
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-cvrm-5hp6-h523.
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
GHSA-cvrm-5hp6-h523 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 358,648 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
simplesamlphp/simplesamlphp-module-casserver🐘simplesamlphp/simplesamlphp-module-casserverReal-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
Summary
The logout endpoint accepts a url query parameter to redirect to. casserver treats that url as trusted, and either (depending on configuration) redirects the browser there, or shows a "you've been logged out" page with a link to continue to that url.
There are a number of other things broken with logout in 7 (cas v3 uses a different query parameters, etc)
Details
Previous module checked the url against the valid service urls.
PoC
The docker instructions from the README.md run an image with a vulnerable config.
Accessing https://localhost/cas/logout?url=https://google.com will redirect to Google
Impact
Impacted configs have
'enable_logout' => true,
and are most impacted if they also have
'skip_logout_page' -> true,
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | simplesamlphp/simplesamlphp-module-casserver | ≥ 7.0.0-rc1&&< 7.0.0 | 7.0.0 |
| 🐘Packagist | simplesamlphp/simplesamlphp-module-casserver | all versions | 6.3.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for simplesamlphp/simplesamlphp-module-casserver. 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 simplesamlphp/simplesamlphp-module-casserver to 7.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cvrm-5hp6-h523 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 GHSA-cvrm-5hp6-h523 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 GHSA-cvrm-5hp6-h523. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-cvrm-5hp6-h523 in your dependencies?
O3 detects GHSA-cvrm-5hp6-h523 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.