CVE-2026-53425
Insufficient Verification of Data Authenticity vulnerability in dropbox samly allows an attacker to establish an authenticated session using a SAML response the service provider never requested.
Overview
CVE-2026-53425 is a known-severity vulnerability. It was published on August 20, 2026.
Technical description
Insufficient Verification of Data Authenticity vulnerability in dropbox samly allows an attacker to establish an authenticated session using a SAML response the service provider never requested.
Samly.SPHandler.validate_authresp/3 in lib/samly/sp_handler.ex validates a SAML response for the SP-initiated flow by comparing only the RelayState value, the IdP identifier, and the presence of a target URL held in the session. It never compares SubjectConfirmationData/@InResponseTo against the ID of the AuthnRequest the service provider issued, and that request ID is never persisted, so no comparison is possible. SAML 2.0 Core section 4.1.4.3 requires a service provider to reject a response whose InResponseTo does not match a request it made. The underlying esaml library checks status, signature, recipient, audience, and staleness, but likewise never inspects InResponseTo, so nothing else closes the gap. Exploitation requires a validly signed assertion from the trusted IdP, which an attacker
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-53425?
CVE-2026-53425 is a known-severity vulnerability. It was published on August 20, 2026.
How severe is CVE-2026-53425?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-53425?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-53425?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-53425 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.