CVE-2026-45156 — Nextcloud: Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDC
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 verificati…
Published: 2026-06-01 · CVSS: 8.1 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7