CVE-2025-54572 — ruby-saml
Fix: SAML-Toolkits/ruby-saml@38ef5ddCVE-2025-54572 is a Uncontrolled Resource Consumption vulnerability in ruby-saml. A fix is available for ruby-saml — see the affected versions and patch details below.
Ruby SAML DOS vulnerability with large SAML response
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-2025-54572.
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.
Real-World Exposure
ruby-samlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
The Ruby SAML library is for implementing the client side of a SAML authorization. In versions 1.18.0 and below, a denial-of-service vulnerability exists in ruby-saml even with the message_max_bytesize setting configured. The vulnerability occurs because the SAML response is validated for Base64 format prior to checking the message size, leading to potential resource exhaustion. This is fixed in version 1.18.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | ruby-saml | all versions | 1.18.1bundle update ruby-saml --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ruby-saml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ruby-saml to 1.18.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-54572 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-2025-54572 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-54572. 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-2025-54572 in your dependencies?
O3 Security finds CVE-2025-54572 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.