GHSA-W4V4-9RW7-5326 Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization

Summary There is a high-severity request-smuggling vulnerability in Traefik's handling of the HTTP/1.1 Upgrade mechanism. Since Traefik moved to unencrypted HTTP/2 with prior knowledge Go 1.24, a client-initiated Upgrade: h2c request header and its connection-specific HTTP2-Settings header were...

Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization

Summary There is a high-severity request-smuggling vulnerability in Traefik's handling of the HTTP/1.1 Upgrade mechanism. Since Traefik moved to unencrypted HTTP/2 with prior knowledge Go 1.24, a client-initiated Upgrade: h2c request header and its connection-specific HTTP2-Settings header were...

CVE-2026-88008 Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching...

EUVD-2026-75545

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching...

CVE-2026-88008 Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching...

CVE-2026-88008

Traefik (open source HTTP reverse proxy and load balancer) versions 2.11.26 through 2.11.57 and 3.7.13 forward a client-supplied Connection header requesting Upgrade: h2c along with HTTP2-Settings to a shared backend. If that backend accepts h2c and returns 101 Switching Protocols , Traefik enter...

h2csmuggler

h2cSmuggler Description h2cSmuggler smuggles HTTP traffic past insecure edge-server proxypass configurations by establishing HTTP/2 cleartext h2c communications with h2c-compatible back-end servers, allowing a bypass of proxy rules and access controls. See my detailed write-up below for: Technica...

PT-2026-89459

Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching...

PT-2026-89702

Summary There is a high-severity request-smuggling vulnerability in Traefik's handling of the HTTP/1.1 Upgrade mechanism. Since Traefik moved to unencrypted HTTP/2 with prior knowledge Go 1.24, a client-initiated Upgrade: h2c request header and its connection-specific HTTP2-Settings header were...

CVE-2026-32136_exploit

CVE-2026-32136exploit - AdGuard Home h2c Upgrade Auth Bypass Unauthenticated authentication bypass in AdGuard Home 0.107.73 via HTTP/2 cleartext h2c upgrade. | ---|--- CVE| CVE-2026-32136 CVSS| 9.8 Critical — AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CWE| CWE-287 Improper Authentication Affected| AdGua...

Exploit for Improper Authentication in Adguard Adguardhome

CVE-2026-32136exploit - AdGuard Home h2c Upgrade Auth Bypass...

Improper Authentication

Overview Affected versions of this package are vulnerable to Improper Authentication via the h2c upgrade process. An attacker can gain unauthorized access by exploiting improper authentication handling during the HTTP/2 Cleartext upgrade. Remediation Upgrade...

CVE-2026-32136 AdGuard Home: HTTP/2 Cleartext (h2c) Upgrade Authentication Bypass

AdGuard Home is a network-wide software for blocking ads and tracking. Prior to 0.107.73, an unauthenticated remote attacker can bypass all authentication in AdGuardHome by sending an HTTP/1.1 request that requests an upgrade to HTTP/2 cleartext h2c. Once the upgrade is accepted, the resulting...

CVE-2026-32136

AdGuard Home (network-wide ad/blocking software) contains a authentication bypass vulnerability CVE-2026-32136. Before 0.107.73, an unauthenticated remote attacker can trigger an HTTP/1.1 upgrade to h2c; after the upgrade is accepted, the inner mux handles subsequent HTTP/2 requests without authe...