Session-token theft via JavaScript-URI form_post redirect
Published Jan 11, 2024 · Updated Jun 17, 2025
Reflected XSS in authentik 2023.10.5 and earlier allows attackers to steal session tokens through a crafted OIDC authorization request. The OAuth2 provider accepts a JavaScript redirect URI with response_mode=form_post and renders the response so the URI receives the current session token. Exploitation requires a user to complete the flow plus either a wildcard-only allowed redirect setting or application-administration rights; token theft enables session hijacking and privilege escalation.
Summary
What happened
Reflected XSS in authentik 2023.10.5 and earlier allows attackers to steal session tokens through a crafted OIDC authorization request. The OAuth2 provider accepts a JavaScript redirect URI with response_mode=form_post and renders the response so the URI receives the current session token. Exploitation requires a user to complete the flow plus either a wildcard-only allowed redirect setting or application-administration rights; token theft enables session hijacking and privilege escalation.
The record
- CVE
- CVE-2024-21637
- Published
- Jan 11, 2024
- Updated
- Jun 17, 2025
- Vendor
- Authentik Security Inc.
- Product
- authentik
- Classifications
- CWE-79, T1539
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 11, 2024CVE publishedPublication date reported by the CVE source.
- Jun 17, 2025Record 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=<= 2023.10.5
- Affected versionversion=<= 2023.8.5
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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