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sensitive dataSSOauthentication

Enterprise SSO: SAML and SCIM pitfalls that show up in production

Published on 2026-04-164 min readCleanIssue

> TL;DR: SSO integration is where most products introduce authentication flaws. The points to review from the vendor side.

What are the common SSO security pitfalls in your product?

SSO is a poisoned gift when mishandled

SSO reassures enterprise buyers. It's also when a product often introduces its worst authentication flaws.

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What tends to break

  • SAML signature not verified or only partially verified;
  • SAML attributes used as identifiers without validation;
  • SCIM that allows account creation without tenant verification;
  • session shared between tenants if the IdP is misconfigured.
  • What an external audit will test

    Replayed SAML requests, tampered attributes, and whether you can get provisioned in a tenant that isn't yours. Those tests are fast and very revealing.

    For software vendors

    CleanIssue specializes in security reviews for software handling sensitive data. If you're building a product, payroll tool, or ATS and want an external review of your exposure before a client audit or security questionnaire, see our offer for software vendors.

    Key Takeaways

  • Always validate SAML assertion issuer and audience — never trust received XML blindly.
  • SCIM provisioning must verify that received attributes match authorized roles.
  • Test SSO with forged assertions to verify your implementation's robustness.
  • Building software? CleanIssue performs security audits for your product in real-world conditions, no source code access needed. For a first read of your exposure, start with an external review of your application.

    Sources

    Written by CleanIssue
    Reviewed on 2026-04-16

    Editorial analysis based on official vendor, project, and regulator documentation.

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