CVE-2026-58066 — CRITICAL (9.8)

Vulnerability Description

Rocket.Chat's SAML SSO before versions 8.7.0, 8.6.1, 8.5.2, 8.4.5, 8.3.7, 8.2.7, 8.1.7, 8.0.8, and 7.10.14 verified XML signatures but did not bind the validated signature to samlp:Response / saml:Assertion. An attacker could submit a wrapped document carrying forged identity attributes alongside any valid signature made by the trusted IdP certificate, and log in as an arbitrary user.

CVSS Score

9.8

CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Related Weaknesses (CWE)

CWE-287

References

FAQ

What is CVE-2026-58066?

CVE-2026-58066 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Rocket.Chat's SAML SSO before versions 8.7.0, 8.6.1, 8.5.2, 8.4.5, 8.3.7, 8.2.7, 8.1.7, 8.0.8, and 7.10.14 verified XML signatures but did not bind the validated signature to samlp:Response / saml:Ass...

How severe is CVE-2026-58066?

CVE-2026-58066 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-58066?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.