CVE-2026-45278
Nextcloud: Open Redirect in user_oidc login flow via protocol-relative URL bypass
Description
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.
INFO
Published Date :
June 1, 2026, 7:16 p.m.
Last Modified :
June 3, 2026, 5:34 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Nextcloud to version 8.2.2.
- Ensure OIDC integration is properly configured.
- Verify user authentication flows.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45278.
| URL | Resource |
|---|---|
| https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8wjr-5cg8-4w73 | Vendor Advisory |
| https://github.com/nextcloud/user_oidc/pull/1273 | Issue Tracking Patch |
| https://hackerone.com/reports/3464925 | Permissions Required |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45278 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45278
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45278 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45278 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 03, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:nextcloud:user_oidc:*:*:*:*:*:*:*:* versions from (including) 6.1.0 up to (excluding) 8.2.2 Added Reference Type GitHub, Inc.: https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8wjr-5cg8-4w73 Types: Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/nextcloud/user_oidc/pull/1273 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://hackerone.com/reports/3464925 Types: Permissions Required -
New CVE Received by [email protected]
Jun. 01, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N Added CWE CWE-601 Added Reference https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8wjr-5cg8-4w73 Added Reference https://github.com/nextcloud/user_oidc/pull/1273 Added Reference https://hackerone.com/reports/3464925