Detections
Analytics

Linux Distros Unpatched Vulnerability : CVE-2021-39191

medium Nessus Plugin ID 252424

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

 - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
 (CVE-2021-39191)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://ubuntu.com/security/CVE-2021-39191

Plugin Details

Severity: Medium

ID: 252424

File Name: unpatched_CVE_2021_39191.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 8/20/2025

Updated: 8/20/2025

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.8

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.5

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N

CVSS Score Source: CVE-2021-39191

CVSS v3

Risk Factor: Medium

Base Score: 6.1

Temporal Score: 5.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libapache2-mod-auth-openidc

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 9/3/2021

Reference Information

CVE: CVE-2021-39191