CVE-2026-45278 PUBLISHED

Nextcloud: Open Redirect in user_oidc login flow via protocol-relative URL bypass

Assigner: GitHub_M
Reserved: 11.05.2026 Published: 01.06.2026 Updated: 02.06.2026

Nextcloud is an open source content collaboration platform. From version 6.1.0 to before version 8.2.2, an attacker can craft links that would redirect users to another website, when the victim uses the attackers link to log in via user OIDC. This issue has been patched in version 8.2.2.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CVSS Score: 3.3

Attack Vector	Local	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	Low
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	nextcloud
Product	security-advisories
Versions	Version >= 6.1.0, < 8.2.2 is affected

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8wjr-5cg8-4w73
https://github.com/nextcloud/user_oidc/pull/1273
https://hackerone.com/reports/3464925

Problem Types

CWE-601: URL Redirection to Untrusted Site ('Open Redirect') CWE