CVE-2026-4349
Duende IdentityServer4 Token Renewal Endpoint authorize improper authentication
- State
- Published
- Severity
- 6.3 Medium
- Published
- Mar 17, 2026
- Updated
- Mar 25, 2026
- Reserved
- Mar 17, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | 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 | VulDB |
| 3.1 | 5.6 Medium | 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 | VulDB |
| 3.0 | 5.6 Medium | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:X | VulDB |
| 2.0 | 5.1 Medium | AV:N/AC:H/Au:N/C:P/I:P/A:P/E:ND/RL:ND/RC:ND | VulDB |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
IdentityServer4Duende |
|
References
- VDB-351380 | Duende IdentityServer4 Token Renewal Endpoint authorize improper authenticationvdb-entrytechnical-description
- VDB-351380 | CTI Indicators (IOB, IOC, IOA)signaturepermissions-required
- Submit #772071 | DuendeSoftware Identity Server 4 Authentication Bypass Issuesthird-party-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.