Vulnerability · Published Aug 10, 2023 · Assigned by GitHub_M

CVE-2023-39953Issuer not verified from obtained token in user_oidc

Medium 4.8

In plain English

A medium-severity security flaw in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).

Severity (CVSS 3.1)4.8Medium

Exploit odds (30 days)0.5%top 54.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
nextcloud	security-advisories	>= 1.0.0, < 1.3.3

Weakness: CWE-303 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xx3h-v363-q36j x_refsource_CONFIRM
https://github.com/nextcloud/user_oidc/pull/642 x_refsource_MISC
https://hackerone.com/reports/2021684 x_refsource_MISC