CVE-2020-27178
HIGHCVE-2020-27178 is a high-severity (CVSS 7.5) vulnerability in org.apereo.cas:cas-server-webapp. O3 Security confirms whether CVE-2020-27178 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Improper Authentication in Apereo CAS
Real-World Exposure
org.apereo.cas:cas-server-webapp☕org.apereo.cas:cas-server-webapp☕org.apereo.cas:cas-server-webapp☕org.apereo.cas:cas-server-support-otp-mfa-core☕org.apereo.cas:cas-server-support-otp-mfa-core☕org.apereo.cas:cas-server-support-otp-mfa-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Apereo CAS 5.3.x before 5.3.16, 6.x before 6.1.7.2, 6.2.x before 6.2.4, and 6.3.x before 6.3.0-RC4 mishandles secret keys with Google Authenticator for multifactor authentication.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apereo.cas:cas-server-webapp | ≥ 5.3.0&&< 5.3.16 | 5.3.16 |
| ☕Maven | org.apereo.cas:cas-server-webapp | ≥ 6.0.0&&< 6.1.7.2 | 6.1.7.2 |
| ☕Maven | org.apereo.cas:cas-server-webapp | ≥ 6.2.0&&< 6.2.4 | 6.2.4 |
| ☕Maven | org.apereo.cas:cas-server-support-otp-mfa-core | ≥ 5.3.0&&< 5.3.16 | 5.3.16 |
| ☕Maven | org.apereo.cas:cas-server-support-otp-mfa-core | ≥ 6.0.0&&< 6.1.7.2 | 6.1.7.2 |
| ☕Maven | org.apereo.cas:cas-server-support-otp-mfa-core | ≥ 6.2.0&&< 6.2.4 | 6.2.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apereo.cas:cas-server-webapp. 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 org.apereo.cas:cas-server-webapp to 5.3.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-27178 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 CVE-2020-27178 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 CVE-2020-27178. 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-2020-27178 in your dependencies?
O3 detects CVE-2020-27178 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.