CVE-2023-39954

Name: CVE-2023-39954
Creator: NVD / NIST
Published: 2023-08-10T15:15:09.693+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.1/10EPSS 0.36%

Last modified Jun 17, 2026

CVE-2023-39954 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. 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, an attacker that obtained at least read access to a snapshot of the database can impersonate the Nextcloud server towards linked servers. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

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, an attacker that obtained at least read access to a snapshot of the database can impersonate the Nextcloud server towards linked servers. user_oidc 1.3.3 contains a patch. No known workarounds are available.

Metrics

CVSS 3.1

8.1/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

0.36%

28.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-311

Affected Software

Vendor	Product	Versions
Nextcloud	User Oidc	>= 1.0.0, < 1.3.3

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-3f92-5c8p-f6gqPatch, Vendor Advisory
https://github.com/nextcloud/user_oidc/pull/636Patch
https://hackerone.com/reports/1994328Permissions Required
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-3f92-5c8p-f6gqPatch, Vendor Advisory
https://github.com/nextcloud/user_oidc/pull/636Patch
https://hackerone.com/reports/1994328Permissions Required

Timeline

Published: Aug 10, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-39954?

How severe is CVE-2023-39954?

CVE-2023-39954 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2023-39954?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-39954?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST