Is CVE-2026-4349 actively exploited?

No active exploitation of CVE-2026-4349 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-4349 be exploited remotely?

Yes. CVE-2026-4349 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-4349?

CVE-2026-4349 has a CVSS score of 5.6 (MEDIUM).

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MEDIUM

CVE-2026-4349

CWE-287Published: March 17, 2026· Updated: Mar 18, 2026

5.6

CVSS v3.1

EPSS:0.06%probability of exploitation in 30 daysPercentile:17.8th

Official Description

A vulnerability was determined in Duende IdentityServer 4. 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. The vendor was contacted early about this disclosure but did not respond in any way.

NVD Source

Technical Analysis

CVE-2026-4349 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

From a weakness classification perspective (CWE-287): Authentication bypass vulnerabilities allow attackers to access protected resources without valid credentials.