CVE-2022-39338: nextcloud openid_connect_user_backend Improper Input Validation

Vulnerability summary

CVE-2022-39338 is a medium (CVSS 5.4) Improper Input Validation vulnerability in nextcloud openid_connect_user_backend. EPSS estimates a 0.63% chance of exploitation in the next 30 days, higher than 49.3% of scored vulnerabilities.

Timeline

1. 25-11-2022
   PublishedVulnerability first disclosed.
2. 23-04-2025
   Last modifiedVulnerability information updated.

Description

user_oidc is an OpenID Connect user backend for Nextcloud. Versions prior to 1.2.1 did not properly validate discovery urls which may lead to a stored cross site scripting attack vector. The impact is limited due to the restrictive CSP that is applied on this endpoint. Additionally this vulnerability has only been shown to be exploitable in the Safari web browser. This issue has been addressed in version 1.2.1. Users are advised to upgrade. Users unable to upgrade should urge their users to avoid using the Safari web browser.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.