CVE-2023-25725

CRITICAL LAB

HAProxy < 2.0.31 - HTTP Request Smuggling via Empty Header Field Names

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2023-25725. PoCs published by krillingws.

AI-analyzed exploit summary This repository contains only a Docker Compose file setting up a lab environment with HAProxy and echo servers, but no actual exploit code or technical details about CVE-2023-25725.

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.

Exploits (1)

nomisec STUB
by krillingws · poc
https://github.com/krillingws/LAB-CVE-2023-25725

This repository contains only a Docker Compose file setting up a lab environment with HAProxy and echo servers, but no actual exploit code or technical details about CVE-2023-25725.

Classification
Stub 90%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: HAProxy (version not specified)
No auth needed
Prerequisites: Docker environment
devstral-2 · analyzed Feb 18, 2026 Full analysis →

Scores

CVSS v3 9.1
EPSS 0.0549
EPSS Percentile 91.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Lab Environment

COMMUNITY
Community Lab
docker pull jmalloc/echo-server:latest
docker pull haproxytech/haproxy-alpine:2.7.2

Details

CWE
CWE-444
Status published
Products (3)
debian/debian_linux 10.0
debian/debian_linux 11.0
haproxy/haproxy < 2.0.31
Published Feb 14, 2023
Tracked Since Feb 18, 2026