CVE-2021-39240: High severity HAProxy HAProxy vulnerability

Published Aug 17, 2021
·
Updated

An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3. It does not ensure that the scheme and path portions of a URI have the expected characters. For example, the authority field (as observed on a target HTTP/2 server) might differ from what the routing rules were intended to achieve.

Affected Software

7 affected componentsFixes available
debian/haproxy
1.8.19-1+deb10u31.8.19-1+deb10u42.2.9-2+deb11u52.6.12-12.6.15-1
HAProxy HAProxy>=2.2.0<2.2.16
HAProxy HAProxy>=2.3.0<2.3.13
HAProxy HAProxy>=2.4.0<2.4.3
Debian Debian Linux=11.0
Fedoraproject Fedora=33
Fedoraproject Fedora=34

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade debian/haproxy to a version that resolves this vulnerability.

    Fixed in 1.8.19-1+deb10u3Fixed in 1.8.19-1+deb10u4Fixed in 2.2.9-2+deb11u5Fixed in 2.6.12-1Fixed in 2.6.15-1

Event History

Aug 17, 2021
CVE Published
via MITRE·06:33 PM
Data Sourced
via MITRE·06:33 PM
Description
Data Sourced
via NVD·07:15 PM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

What is the vulnerability ID for this issue in HAProxy?

The vulnerability ID is CVE-2021-39240.

2

What are the affected versions of HAProxy?

HAProxy versions 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3 are affected.

3

What is the severity level of CVE-2021-39240?

The severity level of CVE-2021-39240 is high with a CVSS score of 7.5.

4

How does CVE-2021-39240 impact HAProxy?

CVE-2021-39240 allows an attacker to bypass routing rules and affect the scheme and path portions of a URI in HAProxy.

5

Is there a fix available for CVE-2021-39240?

Yes, fix versions are available. Please update to HAProxy version 2.2.16, 2.3.13, or 2.4.3 or later.

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