critical 9.1

CVE-2023-25725 json

HAProxy before 2.7.3 may allow a bypass of access control because HTTP/1 headers are inadvertently lost in some situations, aka "request sm…

published 2023-02-14 3 y ago modified 2026-09-08 2 mo ago also BIT-haproxy-2023-25725 , EUVD-2023-29633

cvss: 9.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 5.5%; EPSS 5.5% chance of exploitation in 30 days, percentile 92%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 distros 7

bitnami haproxy 2.0.31, 2.2.29, 2.4.22, 2.5.12, 2.6.9, 2.7.3
haproxy haproxy 2.0.31, 2.2.29, 2.4.22, 2.5.12, 2.6.9, 2.7.3

debian ubuntu red hat suse opensuse almalinux azure linux

haproxy Debian 14, Debian 13, Debian 12 2.6.8-2

debian advisories DEBIAN-CVE-2023-25725

haproxy Ubuntu 18.04 LTS 1.8.8-1ubuntu0.13
haproxy Ubuntu 20.04 LTS 2.0.29-0ubuntu1.3
haproxy Ubuntu 22.04 LTS 2.4.18-0ubuntu1.2
haproxy Ubuntu Pro 16.04 LTS 1.6.3-1ubuntu0.3+esm2

ubuntu advisories UBUNTU-CVE-2023-25725

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

cri-o openshift 4.13 1.26.3-3.rhaos4.13.git641290e.el9
podman openshift 4.13 3:4.4.1-3.rhaos4.13.el8
podman openshift 4.13 3:4.4.1-3.rhaos4.13.el9
skopeo openshift 4.13 2:1.10.0-1.rhaos4.13.el9
buildah openshift 4.13 1:1.29.1-1.rhaos4.13.el9
haproxy openshift 4.13 2.2.24-3.rhaos4.13.el8
haproxy22 openshift 4.13 2.2.24-3.rhaos4.13.el8
openshift openshift 4.13 4.13.0-202304211155.p0.gb404935.assembly.stream.el8

red hat advisories RHSA-2023:1325 RHSA-2023:1268 RHBA-2023:1649 RHSA-2023:1655 RHSA-2023:1978 RHSA-2023:1696

haproxy SLE High Availability Extension 15 SP3, SLE High Availability Extension 15 SP2 2.0.31-150200.11.20.1
haproxy SLE High Availability Extension 15 SP1 2.0.31-150100.8.31.1
haproxy SLE High Availability Extension 15 SP3, SLE High Availability Extension 15 SP2 2.0.14-150200.11.15.1
haproxy SLE High Availability Extension 15 SP1 2.0.14-150100.8.27.1
haproxy SLE Micro 5.3, SLE High Availability Extension 15 SP4, openSUSE Leap Micro 5.3 +1 more 2.4.8+git0.d1f8d41e0-150400.3.10.1

suse advisories SUSE-FU-2023:2119-1 SUSE-FU-2023:2117-1 SUSE-SU-2023:0413-1 SUSE-SU-2023:0412-1 SUSE-SU-2023:0411-1

haproxy openSUSE Tumbleweed 2.7.3+git0.1065b1000-1.1

opensuse advisories openSUSE-SU-2024:12686-1

haproxy AlmaLinux 9 2.4.17-3.el9_1.2

almalinux advisories ALSA-2023:1696

haproxy CBL-Mariner 2.0 2.4.22-1

azure linux advisories AZL-13569

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-25725 updated 2026-11-07 cvss 8.2

haproxy: request smuggling attack in HTTP/1 header parsing

Red Hat OpenShift Container Platform 3.11 haproxy, haproxy18
affected: no fix planned “Out of support scope”
Red Hat Ceph Storage 5.3 Tools rhceph/rhceph-haproxy-rhel8 2.2.19-32
fixed: vendor fix RHSA-2024:0746
Red Hat Enterprise Linux AppStream (v. 9) haproxy 2.4.17-3.el9_1.2
fixed: vendor fix RHSA-2023:1696
Red Hat Enterprise Linux AppStream EUS (v.9.0) haproxy 2.4.7-2.el9_0.2
fixed: vendor fix RHSA-2023:1978
Red Hat OpenShift Container Platform 4.10 haproxy 2.2.19-4.el8, haproxy22 2.2.19-4.el8
fixed: vendor fix RHSA-2023:1655
Red Hat OpenShift Container Platform 4.11 haproxy 2.2.24-3.rhaos4.11.el8, haproxy22 2.2.24-3.rhaos4.11.el8
fixed: vendor fix RHBA-2023:1649
Red Hat OpenShift Container Platform 4.12 haproxy 2.2.24-3.rhaos4.12.el8, haproxy22 2.2.24-3.rhaos4.12.el8
fixed: vendor fix RHSA-2023:1268
Red Hat OpenShift Container Platform 4.13 haproxy 2.2.24-3.rhaos4.13.el8, haproxy22 2.2.24-3.rhaos4.13.el8
fixed: vendor fix RHSA-2023:1325

show 1 more

Red Hat Ironic content for Red Hat OpenShift Container Platform 4.13 tox 3.23.0-2.el9.1, crudini 0.9.3-4.el9, pysnmp 4.4.12-6.el9, future 0.18.2-9.el9.1, subunit 1.4.0-6.el9.1, pyflakes 2.2.0-3.el9.1, +465 more Red Hat Ceph Storage 5.3 Tools rhceph/rhceph-5-rhel8 5-499, rhceph/keepalived-rhel8 2.1.5-39, rhceph/snmp-notifier-rhel8 1.2.1-50, rhceph/rhceph-5-dashboard-rhel8 5-83 Red Hat Enterprise Linux 7 haproxy Red Hat Enterprise Linux 8 haproxy Red Hat OpenShift Container Platform 4.10 perf 4.18.0-305.85.1.el8_4, kernel 4.18.0-305.85.1.el8_4, bpftool 4.18.0-305.85.1.el8_4, toolbox 0.0.9-1.rhaos4.10.el8, jenkins 2.387.1.1680701869-1.el8, kernel-core 4.18.0-305.85.1.el8_4, +45 more Red Hat OpenShift Container Platform 4.11 cri-o 1.24.5-2.rhaos4.11.gitb007cb6.el8, kernel-rt 4.18.0-372.51.1.rt7.208.el8_6, kernel-rt-kvm 4.18.0-372.51.1.rt7.208.el8_6, kernel-rt-core 4.18.0-372.51.1.rt7.208.el8_6, kernel-rt-modules 4.18.0-372.51.1.rt7.208.el8_6, kernel-rt-debug-kvm 4.18.0-372.51.1.rt7.208.el8_6, +10 more

+3 more productsfewer

Red Hat OpenShift Container Platform 4.12 perf 4.18.0-372.49.1.el8_6, kernel 4.18.0-372.49.1.el8_6, bpftool 4.18.0-372.49.1.el8_6, kernel-core 4.18.0-372.49.1.el8_6, kernel-tools 4.18.0-372.49.1.el8_6, python3-perf 4.18.0-372.49.1.el8_6, +36 more Red Hat OpenShift Container Platform 4.13 tini 0.16.1-1.el8ar, grpc 1.18.0-4.el8ost, python-rsa 4.7-1.el8, python3-rsa 4.7-1.el8, cri-tools 1.26.0-1.el9, grpc-cli 1.18.0-4.el8ost, +263 more Red Hat Software Collections rh-haproxy18-haproxy, rh-haproxy18-haproxy-syspaths

not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 19 mo ago (2025-03-20)

Exploit prediction

5.49% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
NVD	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CNA	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
OSV	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
bitnami	haproxy	<2.0.31 >=2.1.0, <2.2.29 >=2.3.0, <2.4.22 >=2.5.0, <2.5.12 >=2.6.0, <2.6.9 >=2.7.0, <2.7.3	2.0.31 2.2.29 2.4.22 2.5.12 2.6.9 2.7.3

Classification

Weakness

CWE-444 Inconsistent Interpretation of HTTP Requests

References

debian.org /security/2023/dsa-5348
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/FPTJQHKUEU2PQ7RWFUYAFLAD4STEIKHU/
vendor-advisory, web
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/JM5NCIBTHYDTLPY2UNC4HO2VAHHE6CJG/
vendor-advisory, web
haproxy.org /
product, web
git.haproxy.org /?p=haproxy-2.7.git%3Ba=commit%3Bh=a0e561ad7f29ed50c473f5a9da664267b60d1112
web
lists.debian.org /debian-lts-announce/2023/02/msg00012.html
mailing-list, third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2023-25725
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary