Description
HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some situations, aka "request smuggling." The HTTP header parsers in HAProxy may accept empty header field names, which could be used to truncate the list of HTTP headers and thus make some headers disappear after being parsed and processed for HTTP/1.0 and HTTP/1.1. For HTTP/2 and HTTP/3, the impact is limited because the headers disappear before being parsed and processed, as if they had not been sent by the client. The fixed versions are 2.7.3, 2.6.9, 2.5.12, 2.4.22, 2.2.29, and 2.0.31.
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 | 2.6.8-2 | — |
| Debian 13 | haproxy | 2.6.8-2 | — |
| Debian 12 | haproxy | 2.6.8-2 | — |
| Debian 11 | haproxy | 2.2.9-2+deb11u4 | DSA-5348-1 |
| Debian 10 | haproxy | 1.8.19-1+deb10u4 | DLA-3318-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | haproxy | 2.4.18-0ubuntu1.2 | USN-5869-1 |
| Ubuntu 20.04 LTS | haproxy | 2.0.29-0ubuntu1.3 | USN-5869-1 |
| Ubuntu 18.04 LTS | haproxy | 1.8.8-1ubuntu0.13 | USN-5869-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | haproxy | 1.6.3-1ubuntu0.3+esm2 | USN-7135-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9 | haproxy | 2.4.17-3.el9_1.2 | RHSA-2023:1696 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 9.0 EUS | haproxy | 2.4.7-2.el9_0.2 | RHSA-2023:1978 |
| Red Hat Openshift Ironic 4 | python-werkzeug +1 | 2.0.3-4.el9 | RHSA-2023:1325 |
| Red Hat OpenShift 4 | buildah +1 | 1:1.29.1-1.rhaos4.13.el9 | RHSA-2023:1325 |
| Red Hat OpenShift 4 | cri-o | 1.24.5-2.rhaos4.11.gitb007cb6.el8 | RHSA-2023:1325, RHBA-2023:1649 |
| Red Hat OpenShift 4 | haproxy +1 | 2.2.19-4.el8 | RHSA-2023:1655, RHSA-2023:1325, RHSA-2023:1268 |
| Red Hat OpenShift 4 | jenkins | 2.387.1.1680701869-1.el8 | RHSA-2023:1655 |
| Red Hat OpenShift 4 | jenkins-2-plugins | 4.10.1680703106-1.el8 | RHSA-2023:1655 |
| Red Hat OpenShift 4 | kernel-rt +15 | 4.18.0-372.51.1.rt7.208.el8_6 | RHBA-2023:1649 |
| Red Hat OpenShift 4 | openshift +1 | 4.10.0-202303221742.p0.g16bcd69.assembly.stream.el7 | RHSA-2023:1655, RHSA-2023:1325, RHSA-2023:1268 |
| Red Hat OpenShift 4 | openshift-clients +1 | 4.13.0-202303241616.p0.g92b1a3d.assembly.stream.el8 | RHSA-2023:1325 |
| Red Hat OpenShift 4 | podman +6 | 3:4.4.1-3.rhaos4.13.el8 | RHSA-2023:1325 |
| Red Hat OpenShift 4 | python-werkzeug +1 | 1.0.1-3.el8ost | RHSA-2023:1325 |
| Red Hat OpenShift 4 | skopeo +1 | 2:1.10.0-1.rhaos4.13.el9 | RHSA-2023:1325 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | haproxy | 2.4.17-3.el9_1.2 | ALSA-2023:1696 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP4 | haproxy | 2.4.8+git0.d1f8d41e0-150400.3.10.1 | SUSE-SU-2023:0411-1 |
| SLES 15 SP3 | haproxy | 2.0.14-150200.11.15.1 | SUSE-SU-2023:0413-1, SUSE-FU-2023:2119-1 |
| SLES 15 SP2 | haproxy | 2.0.14-150200.11.15.1 | SUSE-SU-2023:0413-1, SUSE-FU-2023:2119-1 |
| SLES 15 SP1 | haproxy | 2.0.14-150100.8.27.1 | SUSE-SU-2023:0412-1, SUSE-FU-2023:2117-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 5.3 | haproxy | 2.4.8+git0.d1f8d41e0-150400.3.10.1 | SUSE-SU-2023:0411-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | haproxy | 2.7.3+git0.1065b1000-1.1 | openSUSE-SU-2024:12686-1 |
| openSUSE Leap 15.4 | haproxy | 2.4.8+git0.d1f8d41e0-150400.3.10.1 | SUSE-SU-2023:0411-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap Micro 5.3 | haproxy | 2.4.8+git0.d1f8d41e0-150400.3.10.1 | SUSE-SU-2023:0411-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | haproxy | 2.4.22-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | haproxy | 2.4.17-3.el9_1.2 | ELSA-2023-1696 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
krillingws/LAB-CVE-2023-25725 ★ 0 · Aug 23, 2023
Lab environment to test CVE-2023-25725
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 20
- ALSA-2023:1696 Moderate: haproxy security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2023:1325 Red Hat Security Advisory: OpenShift Container Platform 4.13.0 security update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- RHSA-2023:1268 Red Hat Security Advisory: OpenShift Container Platform 4.12.8 security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHBA-2023:1649 Red Hat Bug Fix Advisory: OpenShift Container Platform 4.11.35 packages and security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2023:1655 Red Hat Security Advisory: OpenShift Container Platform 4.10.56 security update Red Hat Security Advisories (RHSA) · Oct 2, 2026
- WID-SEC-2024-0054 IBM Security Verify Access: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 16, 2026
- USN-7135-1 haproxy vulnerability Ubuntu Security Notices (USN) · Jun 25, 2026
- DSA-5348-1 haproxy - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3318-1 haproxy - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-5869-1 haproxy vulnerability Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-FU-2023:2117-1 Feature update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:0412-1 Security update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-FU-2023:2119-1 Feature update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:0411-1 Security update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2023:0413-1 Security update for haproxy SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:12686-1 haproxy-2.7.3+git0.1065b1000-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2023:1978 Red Hat Security Advisory: haproxy security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2023:1696 Red Hat Security Advisory: haproxy security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- WID-SEC-2023-0361 HAProxy: Schwachstelle ermöglicht Manipulation von Dateien BSI CERT-Bund (WID) · Dec 2, 2024
- ELSA-2023-1696 Moderate: haproxy security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Apr 11, 2023
References
- https://www.haproxy.org/
- https://git.haproxy.org/?p=haproxy-2.7.git%3Ba=commit%3Bh=a0e561ad7f29ed50c473f5a9da664267b60d1112
- [debian-lts-announce] 20230214 [SECURITY] [DLA 3318-1] haproxy security update mailing-list
- DSA-5348 vendor-advisory
- FEDORA-2023-7e04833463 vendor-advisory
- FEDORA-2023-3e8a21cd5b vendor-advisory