Headline
CVE-2023-39953: Issuer not verified from obtained token in user_oidc
user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to. user_oidc 1.3.3 contains a patch. No known workarounds are available.
Package
user_oidc (Nextcloud)
Affected versions
>= 1.0.0
Description
Impact
Missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to.
Patches
It is recommended that the user_oidc app is upgraded to 1.3.3.
Workarounds
No workaround available
References
- HackerOne
- PullRequest
For more information
If you have any questions or comments about this advisory:
- Create a post in nextcloud/security-advisories
- Customers: Open a support ticket at portal.nextcloud.com