CVE-2023-40225 Other in n/a

High 7.2 Published 10 Aug 2023 Updated 9 Oct 2024

HAProxy forwards empty Content-Length headers, potentially allowing HTTP request smuggling against backend servers.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2023-40225?

CVE-2023-40225 is a high-severity vulnerability in n/a, published on 10 Aug 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

HAProxy through 2.0.32, 2.1.x and 2.2.x through 2.2.30, 2.3.x and 2.4.x through 2.4.23, 2.5.x and 2.6.x before 2.6.15, 2.7.x before 2.7.10, and 2.8.x before 2.8.2 forwards empty Content-Length headers, violating RFC 9110 section 8.6. In uncommon cases, an HTTP/1 server behind HAProxy may interpret the payload as an extra request.

Weakness: CWE-444

Which versions are affected by CVE-2023-40225?

1 open source package ship an affected version, including haproxy. It affects 1 product.

Package	Affected	Fixed in
`haproxy` Bitnami	All versions	`2.0.33, 2.2.31, 2.4.24, 2.6.15, 2.7.10, 2.8.2`

Linux distribution packages (23)

`haproxy` Red Hat:openshift:4.11::el8	All versions	`0:2.2.24-4.rhaos4.11.el8`
`haproxy-debugsource` Red Hat:openshift:4.11::el8	All versions	`0:2.2.24-4.rhaos4.11.el8`
`haproxy22` Red Hat:openshift:4.11::el8	All versions	`0:2.2.24-4.rhaos4.11.el8`
`haproxy22-debuginfo` Red Hat:openshift:4.11::el8	All versions	`0:2.2.24-4.rhaos4.11.el8`
`haproxy` Red Hat:openshift:4.12::el8	All versions	`0:2.2.24-4.rhaos4.12.el8`
`haproxy-debugsource` Red Hat:openshift:4.12::el8	All versions	`0:2.2.24-4.rhaos4.12.el8`
`haproxy22` Red Hat:openshift:4.12::el8	All versions	`0:2.2.24-4.rhaos4.12.el8`
`haproxy22-debuginfo` Red Hat:openshift:4.12::el8	All versions	`0:2.2.24-4.rhaos4.12.el8`
`haproxy` Red Hat:openshift:4.13::el8	All versions	`0:2.2.24-4.rhaos4.13.el8`
`haproxy-debugsource` Red Hat:openshift:4.13::el8	All versions	`0:2.2.24-4.rhaos4.13.el8`
`haproxy22` Red Hat:openshift:4.13::el8	All versions	`0:2.2.24-4.rhaos4.13.el8`
`haproxy22-debuginfo` Red Hat:openshift:4.13::el8	All versions	`0:2.2.24-4.rhaos4.13.el8`
`haproxy` SUSE:Linux Enterprise High Availability Extension 15 SP2	All versions	`2.0.31-150200.11.23.1`
`haproxy` SUSE:Linux Enterprise High Availability Extension 15 SP3	All versions	`2.0.31-150200.11.23.1`
`haproxy` SUSE:Linux Enterprise High Availability Extension 15 SP4	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` SUSE:Linux Enterprise High Availability Extension 15 SP5	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` SUSE:Linux Enterprise Micro 5.3	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` SUSE:Linux Enterprise Micro 5.4	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` openSUSE:Leap 15.4	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` openSUSE:Leap 15.5	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` openSUSE:Leap Micro 5.3	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` openSUSE:Leap Micro 5.4	All versions	`2.4.22+git0.f8e3218e2-150400.3.16.1`
`haproxy` openSUSE:Tumbleweed	All versions	`2.8.2+git0.61a0f576a-2.1`

Products include Haproxy Haproxy.

How do I fix CVE-2023-40225?

Upgrade haproxy to a fixed version for your release line: 2.0.33, 2.2.31, 2.4.24 or 2.6.15.

Is CVE-2023-40225 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-40225 exists.

Sources

Also known as AZL-27912, BIT-haproxy-2023-40225, CLSA-2025-1736503350, DEBIAN-CVE-2023-40225, GHSA-xgq7-jp95-v2qv, MGASA-2023-0320 and 10 more.