CVE-2026-45156
Nextcloud: Authentication Bypass in ID4me handling via Missing JWT Signature Verification in User OIDC
HIGH 8.1EPSS 0.6%
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.
- Affected
- nextcloud · security-advisories
- CVSS v3.1 GITHUB
- 8.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N - EPSS
- 0.55% chance of exploitation in the next 30 days, 45th percentile
- Published
- 2026-06-01
- Updated
- 2026-06-03
Proof-of-concept exploits (1)
- cybertechajju/CVE-2026-45156-POC2★ · 2026-06-23