CVE-2026-4349Duende IdentityServer4 Token Renewal Endpoint authorize improper authentication
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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
- 5.6 MEDIUM (v3.1, CNA)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
- Weakness (CWE)
- CWE-287
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulDB
- NVD analysis
- Deferred
- Record last updated
- Mar 25, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Duende IdentityServer4 duende:identityserver4 (from the name) | 4.1.0; 4.1.1; 4.1.2 | CNA record |
References
- https://vuldb.com/?id.351380vdb-entry, technical-description
- https://vuldb.com/?ctiid.351380signature, permissions-required
- https://vuldb.com/?submit.772071third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.