Rocket.Chat SAML Signature Binding Bypass Authentication

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.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

Rocket.Chat versions prior to the specified patches contain a critical SAML SSO vulnerability where XML signatures are validated but not cryptographically bound to the SAML response or assertion. This allows attackers to perform signature wrapping attacks—submitting a forged SAML assertion with identity attributes alongside a valid signature from a trusted Identity Provider, effectively bypassing authentication controls. Organizations using Rocket.Chat as a communication platform with SAML-based SSO are at immediate risk of unauthorized account access, privilege escalation, and lateral movement, particularly in enterprise environments where Rocket.Chat serves as a central collaboration hub.

Casky's 283 matched skills leverage Claude AI's reasoning capabilities to detect the attack patterns associated with MITRE techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky would observe detection patterns spanning XML signature validation bypass techniques, SAML assertion manipulation, and identity spoofing indicators. The platform maps these findings to specific authentication mechanism exploitation (T1556.003) and abuse of existing trust relationships (T1199), enabling security teams to correlate suspicious SAML response structures, signature-assertion mismatches, and impossible user authentication sequences across their identity infrastructure. Extended reasoning helps practitioners understand not just that an attack occurred, but the specific cryptographic binding failure being exploited.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-58066.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

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