CVE-2026-55213 h2o: musl libc stack overflow (QPACK)

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit edd7a120bfc4af11ac0cbebce2a43cc1f93f9af1, when h2o processes a QPACK instruction sent from the peer over HTTP/3, lib/http3/qpack.c might allocate an on-stack buffer as large as approximately 800 KB by calling...

CVE-2026-11352

A flaw was found in curl and libcurl. A malicious HTTP/3 server can exploit an issue in the QUIC UDP receive function by continuously streaming empty UDP datagrams. This can lead to a remote denial of service DoS against a curl or libcurl client, as the helper function discards zero-length UDP...

CVE-2026-9545

A flaw was found in libcurl. An attacker can exploit this by replacing a legitimate HTTP/3 server with an impostor machine. When libcurl attempts a second transfer to the same site with a cached SSL session and early data enabled, it may send sensitive request data before verifying the server's...

ALPINE-CVE-2026-9545

In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL...

ALPINE-CVE-2026-11352

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can...

CVE-2026-11352

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can...

EUVD-2026-41493

In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL...

CVE-2026-11352

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can...

EUVD-2026-41498

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can...

CVE-2026-11352

The CVE-2026-11352 issue affects curl/libcurl: a bug in the QUIC UDP receive path discards zero-length UDP datagrams instead of counting them toward the per-call budget, enabling a connected HTTP/3 peer to continuously send empty datagrams and cause a remote denial-of-service against curl or libc...

BIT-HAPROXY-2026-33555

An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be...

GHSA-JQ4M-Q6P2-8GWC Hackney: Per-chunk timeout with unbounded body accumulation enables slow-drip OOM

Summary hackneyh3:awaitresponseloop/6 in src/hackneyh3.erl accumulates the HTTP/3 response body in memory without any size cap. The after Timeout clause is a per-message inactivity timer, not a wall-clock deadline: every received streamdata chunk, housekeeping select message, or settings frame...

EUVD-2026-31692

Hackney: Cross-origin Redirect Leaks Authorization, Cookie, and Request Body...

CVE-2026-48743

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, Envoy can translate a downstream HTTP/3 request that is complete at the transport layer HEADERS with FIN / headers-only close but still carries a nonzero...

CVE-2026-48743

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, Envoy can translate a downstream HTTP/3 request that is complete at the transport layer HEADERS with FIN / headers-only close but still carries a nonzero...

CVE-2026-48743 Envoy: HTTP/3 to HTTP/1 request smuggling via headers-only request with nonzero Content-Length

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, Envoy can translate a downstream HTTP/3 request that is complete at the transport layer HEADERS with FIN / headers-only close but still carries a nonzero...

CVE-2026-48743

Envoy (open source edge/service proxy) contains a HTTP/3 to HTTP/1 request smuggling vulnerability prior to versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1. A downstream HTTP/3 request that is complete at the transport layer with a nonzero Content-Length can be mistranslated into a complete upstream...

QUIC zero-length UDP datagrams busy-loop

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can...

CURL-CVE-2026-11352 QUIC zero-length UDP datagrams busy-loop

An issue in curl’s QUIC UDP receive function allows a malicious HTTP/3 server to trigger a remote denial of service against a curl or libcurl client. Because the helper function discards zero-length UDP datagrams before counting them toward the per-call packet budget, a connected QUIC peer can...

CVE-2026-53622

Traefik is an HTTP reverse proxy and load balancer. Prior to 3.7.3, there is a critical vulnerability in Traefik's HTTP/3 QUIC TLS configuration selection that allows unauthenticated clients to bypass router-specific mTLS enforcement. When HTTP/3 is enabled on an entrypoint, the TLS handshake...