CVE-2025-27370
CVE-2025-27370 is a medium-severity vulnerability with a CVSS 3.x base score of 6.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-305.
Key facts
- Severity: Medium (CVSS 3.x base score 6.9)
- EPSS exploit prediction: 0% (24th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-5571
- Weakness: CWE-305
- Published:
- Last modified:
Description
OpenID Connect Core through 1.0 errata set 2 allows audience injection in certain situations. When the private_key_jwt authentication mechanism is used, a malicious Authorization Server could trick a Client into writing attacker-controlled values into the audience, including token endpoints or issuer identifiers of other Authorization Servers. The malicious Authorization Server could then use these private key JWTs to impersonate the Client.
Frequently asked questions
- What is CVE-2025-27370?
- OpenID Connect Core through 1.0 errata set 2 allows audience injection in certain situations. When the private_key_jwt authentication mechanism is used, a malicious Authorization Server could trick a Client into writing attacker-controlled values into the audience, including token endpoints or issuer identifiers of other Authorization Servers. The malicious Authorization Server could then use these private key JWTs to impersonate the Client.
- How severe is CVE-2025-27370?
- CVE-2025-27370 has a CVSS 3.x base score of 6.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability none.
- Is CVE-2025-27370 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2025-27370?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2025-27370 have an EU (EUVD) identifier?
- Yes. CVE-2025-27370 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-5571.
- When was CVE-2025-27370 published?
- CVE-2025-27370 was published on 2025-03-03 and last updated on 2026-06-17.
References
- https://eprint.iacr.org/2025/629
- https://github.com/OWASP/ASVS/issues/2678
- https://openid.net/notice-of-a-security-vulnerability/
- https://openid.net/wp-content/uploads/2025/01/OIDF-Responsible-Disclosure-Notice-on-Security-Vulnerability-for-private_key_jwt.pdf
- https://talks.secworkshop.events/osw2025/talk/R8D9BS/
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