Authentication bypass via unchecked SAML assertion conditions
Published Jun 2, 2026 · Updated Jun 2, 2026
Improper SAML validation in authentik before 2025.12.5 or 2026.2.3 allows attackers to replay expired assertions. ResponseProcessor.parse() accepts assertions without enforcing NotBefore, NotOnOrAfter, or AudienceRestriction, including assertions issued for another service provider. Exploitation requires possession of a valid signed SAML assertion and grants authentication after its expiry or outside its intended audience.
Summary
What happened
Improper SAML validation in authentik before 2025.12.5 or 2026.2.3 allows attackers to replay expired assertions. ResponseProcessor.parse() accepts assertions without enforcing NotBefore, NotOnOrAfter, or AudienceRestriction, including assertions issued for another service provider. Exploitation requires possession of a valid signed SAML assertion and grants authentication after its expiry or outside its intended audience.
The record
- CVE
- CVE-2026-41577
- Published
- Jun 2, 2026
- Updated
- Jun 2, 2026
- Vendor
- Authentik Security Inc.
- Product
- authentik
- Classifications
- CWE-345, T1078
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 2, 2026CVE publishedPublication date reported by the CVE source.
- Jun 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2025.12.5
- Affected versionversion=< 2026.2.3
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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