CVE-2026-4349 — Duende IdentityServer4 Token Renewal Endpoint authorize improper authentication
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 E…
Published: 2026-03-17 · CVSS: 6.3 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7