High severity · published Jun 1, 2026
CVE-2026-45284
Nextcloud: Wrong condition in the User OIDC app's LdapService allowed deleted LDAP users to authenticate
8.8
CVSS
0.2%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 9% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SE
security-advisories · nextcloud
>= 1.3.6, < 8.4.0 · source: vendor
UO
User Oidc · Nextcloud
1.3.6 before 8.4.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45284
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45284
Mitigation
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-79xf-ffj8-96fm
Issue Tracking
https://github.com/nextcloud/user_oidc/pull/1340
Permissions Required
https://hackerone.com/reports/3554696
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