Client impersonation via attacker-controlled JWT audiences
Published Mar 3, 2025 · Updated Apr 25, 2025
Audience injection in OpenID Connect Core through 1.0 errata set 2 allows remote attackers to impersonate clients using private_key_jwt. The specification allows a malicious authorization server to make a client place another server's token endpoint or issuer identifier in the signed assertion's audience. Exploitation requires private_key_jwt and interaction with the malicious server, which can reuse the assertion to authenticate as the client elsewhere.
Summary
What happened
Audience injection in OpenID Connect Core through 1.0 errata set 2 allows remote attackers to impersonate clients using private_key_jwt. The specification allows a malicious authorization server to make a client place another server's token endpoint or issuer identifier in the signed assertion's audience. Exploitation requires private_key_jwt and interaction with the malicious server, which can reuse the assertion to authenticate as the client elsewhere.
The record
- CVE
- CVE-2025-27370
- Published
- Mar 3, 2025
- Updated
- Apr 25, 2025
- Vendor
- OpenID Foundation
- Product
- OpenID Connect
- Classifications
- CWE-305, T1550
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 3, 2025CVE publishedPublication date reported by the CVE source.
- Apr 25, 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?
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- Affected versionversion=0 <=1.0 errata set 2
What conditions does exploitation require?
What is affected?
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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