CVE-2026-55203
Fixed in a distro release EPSS <1%CVSS 7.5
HAProxy through 3.4.0, fixed in commit 5985276, contains an integer overflow vulnerability in the fcgi_conn structure's drl field that allows buffer misparse as new FCGI record headers. When contentLength is 65535 and paddingLength is 1 or more, the drl field wraps to 0, causing incorrect record consumption and allowing malicious FastCGI backends to desynchronize the FCGI framing parser, potentially causing request routing errors, response smuggling, or memory safety issues.
Products: haproxy
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 10 | haproxy | 3.0.5-6.el10_2.2 |
| AlmaLinux 9 | haproxy | 2.8.14-3.el9_8.2 |
| Chainguard | haproxy-2.4 | 2.4.36-r0 |
| Chainguard | haproxy-2.6 | 2.6.31-r0 |
| Chainguard | haproxy-2.8 | 2.8.26-r0 |
| Chainguard | haproxy-3.0 | 3.0.24-r0 |
| Chainguard | haproxy-3.1 | no fix |
| Chainguard | haproxy-3.2 | 3.2.20-r0 |
| Chainguard | haproxy-3.3 | 3.3.11-r0 |
| Debian 12 | haproxy | no fix |
| Debian 13 | haproxy | no fix |
| Debian 14 | haproxy | 3.2.20-1 |
| Red Hat Enterprise Linux 10.2 | haproxy | 0:3.0.5-6.el10_2.2 |
| Red Hat Enterprise Linux 10.2 | haproxy-debuginfo | 0:3.0.5-6.el10_2.2 |
| Red Hat Enterprise Linux 10.2 | haproxy-debugsource | 0:3.0.5-6.el10_2.2 |
| Red Hat Enterprise Linux 9 | haproxy | 0:2.8.14-3.el9_8.2 |
| Red Hat Enterprise Linux 9 | haproxy-debuginfo | 0:2.8.14-3.el9_8.2 |
| Red Hat Enterprise Linux 9 | haproxy-debugsource | 0:2.8.14-3.el9_8.2 |
| Red Hat Enterprise Linux eus 10.0 | haproxy | 0:3.0.5-4.el10_0.3 |
| Red Hat Enterprise Linux eus 10.0 | haproxy-debuginfo | 0:3.0.5-4.el10_0.3 |
| Red Hat Enterprise Linux eus 10.0 | haproxy-debugsource | 0:3.0.5-4.el10_0.3 |
| Red Hat hummingbird 1 | haproxy | 0:3.0.25-0.1.hum1 |
| Red Hat rhel e4s 9.2 | haproxy | 0:2.4.17-6.el9_2.5 |
| Red Hat rhel e4s 9.2 | haproxy-debuginfo | 0:2.4.17-6.el9_2.5 |
| Red Hat rhel e4s 9.2 | haproxy-debugsource | 0:2.4.17-6.el9_2.5 |
| Red Hat rhel e4s 9.4 | haproxy | 0:2.4.22-3.el9_4.3 |
| Red Hat rhel e4s 9.4 | haproxy-debuginfo | 0:2.4.22-3.el9_4.3 |
| Red Hat rhel e4s 9.4 | haproxy-debugsource | 0:2.4.22-3.el9_4.3 |
| Red Hat rhel eus 9.6 | haproxy | 0:2.4.22-4.el9_6.3 |
| Red Hat rhel eus 9.6 | haproxy-debuginfo | 0:2.4.22-4.el9_6.3 |
| Red Hat rhel eus 9.6 | haproxy-debugsource | 0:2.4.22-4.el9_6.3 |
| Rocky Linux 10 | haproxy | 0:3.0.5-6.el10_2.2 |
| Rocky Linux 9 | haproxy | 0:2.8.14-3.el9_8.2 |
| SUSE Linux Enterprise High Availability Extension 15 SP4 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.28.1 |
| SUSE Linux Enterprise High Availability Extension 15 SP5 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.28.1 |
| SUSE Linux Enterprise High Availability Extension 15 SP6 | haproxy | 2.8.11+git0.01c1056a4-150600.3.15.1 |
| SUSE Linux Enterprise High Availability Extension 15 SP7 | haproxy | 2.8.11+git0.01c1056a4-150600.3.15.1 |
| SUSE Linux Enterprise High Availability Extension 16.0 | haproxy | 3.2.21+git0.dbe43be37-160000.1.1 |
| SUSE Linux Enterprise Micro 5.3 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.28.1 |
| SUSE Linux Enterprise Micro 5.4 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.28.1 |
| SUSE Linux Enterprise Micro 5.5 | haproxy | 2.4.22+git0.f8e3218e2-150400.3.28.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | haproxy | 3.2.21+git0.dbe43be37-160000.1.1 |
| SUSE Linux Micro 6.0 | haproxy | 2.8.11+git0.01c1056a4-4.1 |
| SUSE Linux Micro 6.1 | haproxy | 2.8.11+git0.01c1056a4-slfo.1.1_4.1 |
| SUSE Linux Micro 6.2 | haproxy | 3.2.21+git0.dbe43be37-160000.1.1 |
| Ubuntu 20.04 LTS | haproxy | no fix |
| Ubuntu 22.04 LTS | haproxy | 2.4.30-0ubuntu0.22.04.2 |
| Ubuntu 24.04 LTS | haproxy | 2.8.16-0ubuntu0.24.04.3 |
| Ubuntu 25.10 | haproxy | 3.0.12-0ubuntu0.25.10.5 |
| Ubuntu 26.04 LTS | haproxy | 3.2.9-1ubuntu2.2 |
| Ubuntu Pro 16.04 LTS | haproxy | no fix |
| Ubuntu Pro 18.04 LTS | haproxy | no fix |
| Wolfi | haproxy-3.2 | 3.2.20-r0 |
| Wolfi | haproxy-3.3 | 3.3.11-r0 |
| openSUSE Leap 16.0 | haproxy | 3.2.21+git0.dbe43be37-160000.1.1 |
| openSUSE Tumbleweed | haproxy | 3.4.0+git31.fc300e9f2-1.1 |