CVE-2021-21606: Input Validation

Published Jan 13, 2021
·
Updated

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier improperly validates the format of a provided fingerprint ID when checking for its existence allowing an attacker to check for the existence of XML files with a short path.

Other sources

Jenkins provides a feature for jobs to store and track fingerprints of files used during a build. Jenkins 2.274 and earlier, LTS 2.263.1 and earlier provides a REST API to check where a given fingerprint was used by which builds. This endpoint does not fully validate that the provided fingerprint ID is properly formatted before checking for the XML metadata for that fingerprint on the controller file system.

This allows attackers with Overall/Read permission to check for the existence of XML files on the controller file system where the relative path can be constructed as 32 characters.

Jenkins 2.275, LTS 2.263.2 validates that a fingerprint ID is properly formatted before checking for its existence.

Affected Software

15 affected componentsFixes available
redhat/jenkins<0:2.263.3.1612433584-1.el7
0:2.263.3.1612433584-1.el7
redhat/conmon<2:2.0.21-1.rhaos4.5.el7
2:2.0.21-1.rhaos4.5.el7
redhat/jenkins<0:2.263.3.1612434332-1.el7
0:2.263.3.1612434332-1.el7
redhat/machine-config-daemon<0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8
0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8
redhat/openshift<0:4.5.0-202102050524.p0.git.0.9229406.el7
0:4.5.0-202102050524.p0.git.0.9229406.el7
redhat/openshift-ansible<0:4.5.0-202102031005.p0.git.0.c6839a2.el7
0:4.5.0-202102031005.p0.git.0.c6839a2.el7
redhat/openshift-clients<0:4.5.0-202102051529.p0.git.3612.61b096a.el8
0:4.5.0-202102051529.p0.git.3612.61b096a.el8
redhat/runc<0:1.0.0-72.rhaos4.5.giteadfc6b.el8
0:1.0.0-72.rhaos4.5.giteadfc6b.el8
redhat/jenkins<0:2.263.3.1612434510-1.el8
0:2.263.3.1612434510-1.el8
maven/org.jenkins-ci.main:jenkins-core>=2.264<=2.274
2.275
maven/org.jenkins-ci.main:jenkins-core<2.263.2
2.263.2
redhat/jenkins<2.275
2.275
redhat/jenkins LTS<2.263.2
2.263.2
Jenkins Jenkins<=2.263.1
Jenkins Jenkins<=2.274

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/jenkins to a version that resolves this vulnerability.

    Fixed in 0:2.263.3.1612433584-1.el7
  2. Upgrade

    Upgrade redhat/conmon to a version that resolves this vulnerability.

    Fixed in 2:2.0.21-1.rhaos4.5.el7
  3. Upgrade

    Upgrade redhat/jenkins to a version that resolves this vulnerability.

    Fixed in 0:2.263.3.1612434332-1.el7
  4. Upgrade

    Upgrade redhat/machine-config-daemon to a version that resolves this vulnerability.

    Fixed in 0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8
  5. Upgrade

    Upgrade redhat/openshift to a version that resolves this vulnerability.

    Fixed in 0:4.5.0-202102050524.p0.git.0.9229406.el7
  6. Upgrade

    Upgrade redhat/openshift-ansible to a version that resolves this vulnerability.

    Fixed in 0:4.5.0-202102031005.p0.git.0.c6839a2.el7
  7. Upgrade

    Upgrade redhat/openshift-clients to a version that resolves this vulnerability.

    Fixed in 0:4.5.0-202102051529.p0.git.3612.61b096a.el8
  8. Upgrade

    Upgrade redhat/runc to a version that resolves this vulnerability.

    Fixed in 0:1.0.0-72.rhaos4.5.giteadfc6b.el8
  9. Upgrade

    Upgrade redhat/jenkins to a version that resolves this vulnerability.

    Fixed in 0:2.263.3.1612434510-1.el8
  10. Upgrade

    Upgrade maven/org.jenkins-ci.main:jenkins-core to a version that resolves this vulnerability.

    Fixed in 2.275
  11. Upgrade

    Upgrade maven/org.jenkins-ci.main:jenkins-core to a version that resolves this vulnerability.

    Fixed in 2.263.2
  12. Upgrade

    Upgrade redhat/jenkins to a version that resolves this vulnerability.

    Fixed in 2.275
  13. Upgrade

    Upgrade redhat/jenkins LTS to a version that resolves this vulnerability.

    Fixed in 2.263.2

Event History

Jan 13, 2021
CVE Published
12:00 AM
CVE Published
via MITRE·03:55 PM
Data Sourced
via MITRE·03:55 PM
Description
Feb 4, 2021
Data Sourced
via Red Hat·01:59 PM
DescriptionSeverityAffected Software
May 24, 2022
Advisory Published
05:39 PM

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2021-21606?

CVE-2021-21606 is rated as a medium severity vulnerability.

2

How do I fix CVE-2021-21606?

To fix CVE-2021-21606, upgrade Jenkins to version 2.275 or later, or LTS version 2.263.2 or later.

3

What versions of Jenkins are affected by CVE-2021-21606?

Versions of Jenkins up to and including 2.274 and LTS versions up to and including 2.263.1 are affected by CVE-2021-21606.

4

What does CVE-2021-21606 allow an attacker to do?

CVE-2021-21606 allows an attacker to improperly check for the existence of XML files with short paths.

5

Is there a workaround for CVE-2021-21606?

There is no official workaround for CVE-2021-21606, so upgrading is the recommended approach.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203