Vulnerability in Nextcloud Security-Advisories
CVE-2023-39953
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.005 (43.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Nextcloud Security-Advisories — versions >= 1.0.0, < 1.3.3
- Nextcloud User Oidc
Weakness classification (CWE)
References
- github.com/nextcloud/security-advisories/security/advisories/GHSA-xx3h-v363-q36j (Patch, Vendor Advisory)
- github.com/nextcloud/user_oidc/pull/642 (Patch)
- hackerone.com/reports/2021684 (Permissions Required)
Frequently asked questions
- What is CVE-2023-39953?
- CVE-2023-39953 is a medium-severity vulnerability in Nextcloud Security-Advisories, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 4.8/10. Published 2023-08-10.
- How severe is CVE-2023-39953?
- Medium severity. CVSS v3 base score is 4.8 out of 10.