CVE-2026-4349

MEDIUM 5.6

Duende IdentityServer4 Token Renewal Endpoint authorize improper authentication

CVSS Score

5.6

EPSS Score

0.1%

EPSS Percentile

21th

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.

CWE	CWE-287
Vendor	duende
Product	identityserver4
Published	Mar 17, 2026
Last Updated	Mar 25, 2026

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CVSS v3 Breakdown

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

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

Affected Versions

Duende / IdentityServer4

4.1.0 4.1.1 4.1.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

vuldb.com: https://vuldb.com/?id.351380 vuldb.com: https://vuldb.com/?ctiid.351380 vuldb.com: https://vuldb.com/?submit.772071

Credits

🔍 Edcarlos (VulDB User) VulDB