CVE-2026-4349
Duende IdentityServer4 Token Renewal Endpoint authorize improper authentication
Vexday Risk Score
13Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 6.3EPSS 0.4%KEV nãoPoC —Nuclei —Metasploit —Patch —
Lifecycle
17 Mar 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X
Affected products
Duende · IdentityServer4