CVE-2018-6519 — simplesamlphp/saml2
HIGHCVE-2018-6519 is a high-severity (CVSS 7.5) CWE-74 vulnerability in simplesamlphp/saml2. A fix is available for simplesamlphp/saml2 — see the affected versions and patch details below.
SimpleSAMLphp SAML2 library Regular Expression Denial of Service vulnerability
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-2018-6519 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
simplesamlphp/saml2🐘simplesamlphp/saml2🐘simplesamlphp/saml2Real-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
The SAML2 library before 1.10.4, 2.x before 2.3.5, and 3.x before 3.1.1 in SimpleSAMLphp has a Regular Expression Denial of Service vulnerability for fraction-of-seconds data in a timestamp.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | simplesamlphp/saml2 | all versions | 1.10.4composer require simplesamlphp/saml2:^1.10.4 |
| 🐘Packagist | simplesamlphp/saml2 | ≥ 2.0&&< 2.3.5 | 2.3.5composer require simplesamlphp/saml2:^2.3.5 |
| 🐘Packagist | simplesamlphp/saml2 | ≥ 3.0&&< 3.1.1 | 3.1.1composer require simplesamlphp/saml2:^3.1.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for simplesamlphp/saml2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update simplesamlphp/saml2 to 1.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-6519 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-2018-6519 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-6519. 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-2018-6519 in your dependencies?
O3 Security finds CVE-2018-6519 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.