CVE Vulnerabilities

CVE-2021-21695

Improper Link Resolution Before File Access ('Link Following')

Published: Nov 04, 2021 | Modified: Nov 22, 2023
CVSS 3.x
8.8
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 2.x
6.8 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
9 IMPORTANT
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Ubuntu

FilePath#listFiles lists files outside directories that agents are allowed to access when following symbolic links in Jenkins 2.318 and earlier, LTS 2.303.2 and earlier.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Name Vendor Start Version End Version
Jenkins Jenkins * 2.303.3 (excluding)
Jenkins Jenkins * 2.319 (excluding)
Red Hat OpenShift Container Platform 3.11 RedHat jenkins-0:2.303.3.1637698110-1.el7 *
Red Hat OpenShift Container Platform 4.6 RedHat jenkins-0:2.303.3.1637597493-1.el8 *
Red Hat OpenShift Container Platform 4.7 RedHat jenkins-0:2.303.3.1637597018-1.el8 *
Red Hat OpenShift Container Platform 4.8 RedHat jenkins-0:2.303.3.1637596565-1.el8 *
Red Hat OpenShift Container Platform 4.9 RedHat jenkins-0:2.303.3.1637595827-1.el8 *

Potential Mitigations

  • Follow the principle of least privilege when assigning access rights to entities in a software system.
  • Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References