Medium severity · published Aug 10, 2023
CVE-2023-39953
user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform
4.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
UO
User Oidc · Nextcloud
1.0.0 before 1.3.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-39953
CVE.org
https://www.cve.org/CVERecord?id=CVE-2023-39953
Patch
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xx3h-v363-q36j
Patch
https://github.com/nextcloud/user_oidc/pull/642
Permissions Required
https://hackerone.com/reports/2021684
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