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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | haproxy | 2.6.15-1 | — |
| Debian 13 | haproxy | 2.6.15-1 | — |
| Debian 12 | haproxy | 2.6.12-1+deb12u1 | DSA-5590-1 |
| Debian 11 | haproxy | 2.2.9-2+deb11u6 | DSA-5590-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | haproxy | 2.4.22-0ubuntu0.22.04.2 | USN-6294-1 |
| Ubuntu 20.04 LTS | haproxy | 2.0.31-0ubuntu0.2 | USN-6294-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | haproxy | 2.4.22-3.el9_3 | RHSA-2024:1142 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.2 EUS | haproxy | 2.4.17-6.el9_2.2 | RHSA-2024:1089 |
| Red Hat Openshift Ironic 4 | python-werkzeug +1 | 2.2.3-2.el9 | RHSA-2023:7473 |
| Red Hat OpenShift 4 | haproxy +1 | 2.2.24-4.rhaos4.11.el8 | RHSA-2024:0308, RHSA-2024:0200, RHSA-2023:7606 |
| Red Hat OpenShift 4 | haproxy26 | 2.6.13-2.rhaos4.14.el8 | RHSA-2023:7473 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | haproxy | 2.4.22-3.el9_3 | ALSA-2024:1142 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
| SLES 15 SP4 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
| SLES 15 SP3 | haproxy | 2.0.31-150200.11.23.1 | SUSE-SU-2023:3490-1 |
| SLES 15 SP2 | haproxy | 2.0.31-150200.11.23.1 | SUSE-SU-2023:3490-1 |
| SLES 15 SP1 | haproxy | 2.0.31-150100.8.34.1 | SUSE-SU-2023:4646-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 5.4 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
| SLE Micro 5.3 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | haproxy | 2.8.2+git0.61a0f576a-2.1 | openSUSE-SU-2024:13116-1 |
| openSUSE Leap 15.5 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
| openSUSE Leap 15.4 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap Micro 5.4 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
| openSUSE Leap Micro 5.3 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.16.1 | SUSE-SU-2023:3469-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | haproxy | 2.8.0-1.amzn2023.0.2 | ALAS2023-2023-293 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | haproxy | 2.4.24-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | haproxy | 2.4.22-3.el9_3 | ELSA-2024-1142 |
Advisories 18
- ALSA-2024:1142 Moderate: haproxy security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2023:7473 Red Hat Security Advisory: OpenShift Container Platform 4.14.4 packages and security update Red Hat Security Advisories (RHSA) · Aug 19, 2026
- RHSA-2024:1142 Red Hat Security Advisory: haproxy security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2024:1089 Red Hat Security Advisory: haproxy security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2024:0308 Red Hat Security Advisory: OpenShift Container Platform 4.11.57 packages and security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2024:0200 Red Hat Security Advisory: OpenShift Container Platform 4.12.47 security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- RHSA-2023:7606 Red Hat Security Advisory: OpenShift Container Platform 4.13.25 packages and security update Red Hat Security Advisories (RHSA) · Aug 5, 2026
- WID-SEC-2024-0054 IBM Security Verify Access: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 16, 2026
- DSA-5590-1 haproxy - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-6294-1 haproxy vulnerability Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-6294-2 haproxy vulnerability Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2023:3490-1 Security update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:13116-1 haproxy-2.8.2+git0.61a0f576a-2.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:3469-1 Security update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:4646-1 Security update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2023-2041 HAProxy Enterprise: Schwachstelle ermöglicht Darstellen falscher Informationen BSI CERT-Bund (WID) · Mar 6, 2024
- ELSA-2024-1142 Moderate: haproxy security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Mar 6, 2024
- ALAS2023-2023-293 Moderate: haproxy security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 23, 2023
References
- https://github.com/haproxy/haproxy/issues/2237
- https://github.com/haproxy/haproxy/commit/6492f1f29d738457ea9f382aca54537f35f9d856
- https://www.haproxy.org/download/2.8/src/CHANGELOG
- https://www.haproxy.org/download/2.7/src/CHANGELOG
- https://www.haproxy.org/download/2.6/src/CHANGELOG
- https://cwe.mitre.org/data/definitions/436.html