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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.

PUBLISHED Reserved 2026-03-17 | Published 2026-03-17 | Updated 2026-03-25 | Assigner VulDB




MEDIUM: 6.3CVSS: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
MEDIUM: 5.6CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:X
MEDIUM: 5.6CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:X
5.1AV:N/AC:H/Au:N/C:P/I:P/A:P/E:ND/RL:ND/RC:ND

Problem types

Improper Authentication

Product status

4.1.0
affected

4.1.1
affected

4.1.2
affected

Timeline

2026-03-17:Advisory disclosed
2026-03-17:VulDB entry created
2026-03-25:VulDB entry last update

Credits

Edcarlos (VulDB User) reporter

VulDB coordinator

References

vuldb.com/?id.351380 (VDB-351380 | Duende IdentityServer4 Token Renewal Endpoint authorize improper authentication) vdb-entry technical-description

vuldb.com/?ctiid.351380 (VDB-351380 | CTI Indicators (IOB, IOC, IOA)) signature permissions-required

vuldb.com/?submit.772071 (Submit #772071 | DuendeSoftware Identity Server 4 Authentication Bypass Issues) third-party-advisory

cve.org (CVE-2026-4349)

nvd.nist.gov (CVE-2026-4349)

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