Authentication bypass via untrusted SAML signing certificates
Published Aug 5, 2025 · Updated Feb 26, 2026
Authentication bypass in Zscaler Authentication Server before 6.2r allows attackers to register a device as a targeted user. The /sfc_sso endpoint accepts SAML assertions signed by any certificate instead of checking the configured IdP public key, then issues a valid JWT. Exploitation requires the target user's email and a SAML-enabled tenant but no privileged access to the IdP.
Summary
What happened
Authentication bypass in Zscaler Authentication Server before 6.2r allows attackers to register a device as a targeted user. The /sfc_sso endpoint accepts SAML assertions signed by any certificate instead of checking the configured IdP public key, then issues a valid JWT. Exploitation requires the target user's email and a SAML-enabled tenant but no privileged access to the IdP.
The record
- CVE
- CVE-2025-54982
- Published
- Aug 5, 2025
- Updated
- Feb 26, 2026
- Vendor
- Zscaler
- Product
- Zscaler Authentication Server
- Classifications
- CWE-347, CAPEC-114, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 5, 2025CVE publishedPublication date reported by the CVE source.
- Feb 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <6.2r
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- AmberWolf SAML authentication-bypass proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo