CVE-2026-109575
Published:October 12, 2026
Updated:October 13, 2026
In HAProxy Data Plane API 2.2.0 through 3.4.3 (and corresponding Enterprise Edition releases), Server.ConfigureAPI() has process-global authentication logic that improperly drops security controls across multiple transport types. When a TLS Certificate Authority (tls_ca) is configured and a numeric TLS port (tls_port) is specified, the application globally disables Basic authentication on its shared internal request handler. Because this handler is shared concurrently among HTTP, HTTPS, and UNIX domain socket listeners, and mutual TLS (mTLS) client certificate verification (tls.RequireAndVerifyClientCert) is enforced exclusively on the HTTPS server path, all other simultaneously active non-mTLS listeners fail open. Consequently, an unauthenticated attacker capable of reaching an affected HTTP or UNIX management endpoint can completely bypass credentials to gain full API administrative access. This allows unauthorized remote or local actors to read sensitive, cleartext HAProxy configuration data or replace the managed configuration entirely via the raw configuration endpoint. This has been fixed in versions 3.4.4, 3.3.9, 3.2.17, 3.0.25, 2.9.29, and their respective EE backports by migrating to a per-request TLS connection-state validation model.
Affected Packages
https://github.com/haproxytech/dataplaneapi.git (GITHUB):
Affected version(s) >=v3.4.0 <v3.4.4Fix Suggestion:
Update to version v3.4.4github.com/haproxytech/dataplaneapi (GO):
Affected version(s) >=v1.2.5-0.20210407121242-8cbfdd325569 <v1.2.5-0.20261009112702-638676e1cfd2Fix Suggestion:
Update to version v1.2.5-0.20261009112702-638676e1cfd2Related Resources (5)
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Contact UsCVSS v4
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
9.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Missing Authentication for Critical Function
EPSS
Base Score:
0.36