CVE-2024-49755: Duende IdentityServer is an OpenID Connect and OAuth 2.x framework for ASP.NET Core. IdentityServer's local API authentication handler performs insuff...

Description

Duende IdentityServer is an OpenID Connect and OAuth 2.x framework for ASP.NET Core. IdentityServer's local API authentication handler performs insufficient validation of the cnf claim in DPoP access tokens. This allows an attacker to use leaked DPoP access tokens at local api endpoints even without possessing the private key for signing proof tokens. Note that this only impacts custom endpoints within an IdentityServer implementation that have explicitly used the LocalApiAuthenticationHandler for authentication. This vulnerability is patched in IdentityServer 7.0.8. Version 6.3 and below are unaffected, as they do not support DPoP in Local APIs.

Metrics

CVSS 3.1

3.1/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

EPSS Probability

0.32%

23.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

References

Timeline

Published: Oct 28, 2024
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2024-49755?

Duende IdentityServer is an OpenID Connect and OAuth 2.x framework for ASP.NET Core. IdentityServer's local API authentication handler performs insufficient validation of the cnf claim in DPoP access tokens. This allows an attacker to use leaked DPoP access tokens at local api endpoints even without possessing the private key for signing proof tokens. Note that this only impacts custom endpoints within an IdentityServer implementation that have explicitly used the LocalApiAuthenticationHandler for authentication. This vulnerability is patched in IdentityServer 7.0.8. Version 6.3 and below are unaffected, as they do not support DPoP in Local APIs.

How severe is CVE-2024-49755?

CVE-2024-49755 has a CVSS score of 3.1/10 (LOW severity). The EPSS model estimates a 0.32% probability of exploitation in the next 30 days.

How do I fix CVE-2024-49755?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.