8.1High
CVE-2026-45156Nextcloud: Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDC
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.
Weakness (CWE):
CWE-287
Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.
Affected products and versions
| Vendor | Product | Versions | |
|---|---|---|---|
| nextcloud | security-advisories | >= 0.3.0, < 3.1.0, >= 5.0.0, < 5.1.0, >= 6.0.0, < 6.4.0 |