CVE-2026-45156

high

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.

References

https://hackerone.com/reports/3489490

https://github.com/nextcloud/user_oidc/pull/1285

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qqgv-fqwp-mjpp

Details

Source: Mitre, NVD

Published: 2026-06-01

Updated: 2026-06-01

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 8.1

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

Severity: High

EPSS

EPSS: 0.00028