Vulnerability in Rocket.Chat's SAML SSO leading to unauthorized user access

CVE-2026-58066

What is CVE-2026-58066?

A vulnerability in Rocket.Chat's SAML Single Sign-On (SSO) allows attackers to exploit improper XML signature validation. Specifically, the system verifies XML signatures but fails to associate the validated signature with the samlp:Response or saml:Assertion. This oversight enables malicious actors to send a wrapped document with forged identity attributes while utilizing a valid signature from a trusted Identity Provider (IdP) certificate, potentially gaining unauthorized access to user accounts. Users of affected versions are strongly advised to upgrade to secure versions to mitigate risks.

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