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Vulnerability record · CVE-2026-45284 · published 1 June 2026

CVE-2026-45284: Nextcloud user oidc improper access control vulnerability

Nextcloud · User Oidc

Nextcloud is an open source content collaboration platform. From version 1.3.6 to before version 8.4.0, an improper check allowed users that where provided by LDAP to still authenticate towards user OIDC after they where deleted. This issue has been patched in version 8.4.0.

8.8 CVSS 3.1 High EPSS 0.36% · top 72.4% CWE-284 · Improper access control
8.8CVSS 3.1 base score
0.36%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
22 Jul 2026Last modified by NVD

Description

Nextcloud is an open source content collaboration platform. From version 1.3.6 to before version 8.4.0, an improper check allowed users that where provided by LDAP to still authenticate towards user OIDC after they where deleted. This issue has been patched in version 8.4.0.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-79xf-ffj8-96fm MitigationVendor Advisory
https://github.com/nextcloud/user_oidc/pull/1340 Issue TrackingPatch
https://hackerone.com/reports/3554696 Permissions Required

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2023-32074Nextcloud user oidc improper restriction of authentication attempts vulnerabilityuser_oidc app is an OpenID Connect user backend for Nextcloud. Authentication can be broken/bypassed in user_oidc app. It is recommended that the Nex…EPSS 0.85%8.1CVE-2023-39954Nextcloud user oidc missing encryption vulnerabilityuser_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, …EPSS 0.44%6.3CVE-2024-37312Nextcloud user oidc improper access control vulnerabilityuser_oidc app is an OpenID Connect user backend for Nextcloud. Missing access control on the ID4me endpoint allows an attacker to register an account…EPSS 0.64%6.1CVE-2026-45278Nextcloud user oidc open redirect vulnerabilityNextcloud is an open source content collaboration platform. From version 6.1.0 to before version 8.2.2, an attacker can craft links that would redire…EPSS 0.32%6.1CVE-2024-52512Nextcloud user oidc open redirect vulnerabilityuser_oidc app is an OpenID Connect user backend for Nextcloud. A malicious user could send a malformed login link that would redirect the user to a p…EPSS 0.42%5.4CVE-2023-28848Nextcloud user oidc cross-site request forgery vulnerabilityuser_oidc is the OIDC connect user backend for Nextcloud, an open source collaboration platform. A vulnerability in versions 1.0.0 until 1.3.0 effect…EPSS 0.33%4.8CVE-2023-39953Nextcloud user oidc vulnerabilityuser_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, …EPSS 0.54%4.7CVE-2024-37886Nextcloud user oidc improper verification of cryptographic signature vulnerabilityuser_oidc app is an OpenID Connect user backend for Nextcloud. An attacker could potentially trick the app into accepting a request that is not signe…EPSS 0.24%

Source: NIST National Vulnerability Database (record CVE-2026-45284), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.