libcurl 8.11.0 < 8.21.0 HTTP/3 Early Data Information Disclosure (CVE-2026-9545)

The version of libcurl installed on the remote host is 8.11.0 prior to 8.21.0. It is, therefore, affected by an information disclosure vulnerability: - When libcurl returns to a hostname with a cached SSL session and early data enabled, libcurl might send the request bytes before enforcing the...

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...

Improper Certificate Validation

Overview Affected versions of this package are vulnerable to Improper Certificate Validation when the CURLOPTSSLSESSIONIDCACHE is enabled and the CURLSSLOPTEARLYDATA option is set in CURLOPTSSLOPTIONS. An attacker can intercept and obtain sensitive information by impersonating a server and...

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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...

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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...

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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-2026-9545 exposing HTTP/3 early data

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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-2026-9545

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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...

Curl 8.11.0 < 8.21.0 HTTP/3 Early Data Information Disclosure

The version of curl installed on the remote host is 8.11.0 prior to 8.21.0. It is, therefore, affected by an information disclosure vulnerability: - When libcurl returns to a hostname with a cached SSL session and early data enabled, libcurl might send the request bytes before enforcing the...

UBUNTU-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...

exposing HTTP/3 early data

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...

CURL-CVE-2026-9545 exposing HTTP/3 early data

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...

PT-2026-51754

Name of the Vulnerable Software and Affected Versions libcurl affected versions not specified Description An issue exists where libcurl may send request data on a new connection before enforcing certificate verification failure. This occurs when a user first connects to a legitimate HTTP/3 server...

curl: CVE-2026-9545: exposing HTTP/3 early data

Summary: When the ngtcp2 HTTP/3 backend reuses a TLS session that advertises early data support, cfngtcp2onsessionreuse initializes the HTTP/3 connection state and marks the connection filter as connected before the new QUIC/TLS handshake has completed. The request send path can then reach...

JLSEC-2026-249 Issue summary: Some non-default TLS server configurations can cause unbounded memory growth when...

Issue summary: Some non-default TLS server configurations can cause unbounded memory growth when processing TLSv1.3 sessions Impact summary: An attacker may exploit certain server configurations to trigger unbounded memory growth that would lead to a Denial of Service This problem can occur in...

SUSE CVE-2025-64763

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwardi...

CVE-2025-64763

A flaw was found in Envoy. This vulnerability allows a de-synchronized CONNECT tunnel state via accepting client data before issuing a 2xx response and forwarding it to the upstream TCP Transmission Control Protocol connection when configured in TCP Transmission Control Protocol proxy mode to...

BIT-ENVOY-2025-64763 Envoy forwards early CONNECT data in TCP proxy mode

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwardi...

EUVD-2025-201099

Envoy forwards early CONNECT data in TCP proxy mode...

CVE-2025-64763 Envoy forwards early CONNECT data in TCP proxy mode

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwardi...