CVE-2026-45156

Description

Nextcloud is an open source content collaboration platform. From versions 0.3.0 to before 3.1.0, 5.0.0 to before 5.1.0, and 6.0.0 to before 6.4.0, a missing signature verification in User OIDC allowed a malicious ID4me authority to identify as any user. This issue has been patched in versions 3.1.0, 4.1.0, 5.1.0, 6.4.0 and 8.3.0.

PUBLISHED Reserved 2026-05-08 | Published 2026-06-01 | Updated 2026-06-03 | Assigner GitHub_M

Problem types

CWE-287: Improper Authentication

Product status

References

github.com/...sories/security/advisories/GHSA-qqgv-fqwp-mjpp

github.com/nextcloud/user_oidc/pull/1285

hackerone.com/reports/3489490

cve.org (CVE-2026-45156)

nvd.nist.gov (CVE-2026-45156)

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