CVE-2023-39953

Issuer not verified from obtained token in user_oidc

Description

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.

Category

4.8
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.49%
Vendor Advisory github.com
Affected: nextcloud security-advisories
Published at:
Updated at:

References

Link Tags
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xx3h-v363-q36j patch vendor advisory
https://github.com/nextcloud/user_oidc/pull/642 patch
https://hackerone.com/reports/2021684 permissions required

Frequently Asked Questions

What is the severity of CVE-2023-39953?
CVE-2023-39953 has been scored as a medium severity vulnerability.
How to fix CVE-2023-39953?
To fix CVE-2023-39953, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2023-39953 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2023-39953 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-39953?
CVE-2023-39953 affects nextcloud security-advisories.
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