CVE-2026-4349
Improper Authentication in Duende IdentityServer Token Renewal Endpoint
Publication date: 2026-03-17
Last updated on: 2026-03-25
Assigner: VulDB
Description
Description
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| duende | identityserver | 4 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-287 | When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in Duende IdentityServer 4, specifically in an unknown function within the /connect/authorize file related to the Token Renewal Endpoint.
The issue arises from manipulation of the argument id_token_hint, which leads to improper authentication.
An attacker can exploit this vulnerability remotely, but the attack is considered to have high complexity and is difficult to execute.
The vendor was contacted early about this issue but did not respond.
How can this vulnerability impact me? :
This vulnerability can lead to improper authentication, which means an attacker might be able to bypass normal authentication mechanisms.
As a result, unauthorized users could potentially gain access to protected resources or perform actions they should not be allowed to.
The CVSS scores indicate a moderate impact on confidentiality, integrity, and availability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
I don't know