CVE-2026-109575 Auth bypass in Data Plane API CE
Unauthenticated attackers can bypass authentication on HTTP or UNIX listeners to gain full administrative access and modify HAProxy configurations when TLS CA is configured.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109575?
CVE-2026-109575 is a critical authentication bypass vulnerability in HAProxy Data Plane API CE, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-306
Which versions are affected by CVE-2026-109575?
How do I fix CVE-2026-109575?
No fix has been published for CVE-2026-109575 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-109575 being exploited?
There is no known exploitation of CVE-2026-109575 in the wild and no public exploit code.
Sources
Also known as GHSA-7jqw-rhp8-c8vf.