CVE-2026-4349 — MEDIUM (5.6)

Vulnerability Description

A vulnerability was determined in Duende IdentityServer4 up to 4.1.2. The affected element is an unknown function of the file /connect/authorize of the component Token Renewal Endpoint. This manipulation of the argument id_token_hint causes improper authentication. It is possible to initiate the attack remotely. The attack is considered to have high complexity. The exploitability is described as difficult. This vulnerability only affects products that are no longer supported by the maintainer.

CVSS Score

5.6

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

LOW

Integrity

LOW

Availability

LOW

Related Weaknesses (CWE)

CWE-287

References

FAQ

What is CVE-2026-4349?

CVE-2026-4349 is a vulnerability with a CVSS score of 5.6 (MEDIUM). A vulnerability was determined in Duende IdentityServer4 up to 4.1.2. The affected element is an unknown function of the file /connect/authorize of the component Token Renewal Endpoint. This manipulat...

How severe is CVE-2026-4349?

CVE-2026-4349 has been rated MEDIUM with a CVSS base score of 5.6/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-4349?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.