CVE-2023-44487

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

CVE-2017-10868

H2O version 2.2.2 and earlier allows remote attackers to cause a denial of service in the server via specially crafted HTTP/1 header.

CVE-2021-43848

h2o is an open source http server. In code prior to the 8c0eca3 commit h2o may attempt to access uninitialized memory. When receiving QUIC frames in certain order, HTTP/3 server-side implementation of h2o can be misguided to treat uninitialized memory as HTTP/3 frames that have been received. When ...

CVE-2017-10869

Buffer overflow in H2O version 2.2.2 and earlier allows remote attackers to cause a denial-of-service in the server via unspecified vectors.

CVE-2017-10908

H2O version 2.2.3 and earlier allows remote attackers to cause a denial of service in the server via specially crafted HTTP/2 header.

CVE-2024-45403

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When h2o is configured as a reverse proxy and HTTP/3 requests are cancelled by the client, h2o might crash due to an assertion failure. The crash can be exploited by an attacker to mount a Denial-of-Service attack. By default, the ...

CVE-2024-45397

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When an HTTP request using TLS/1.3 early data on top of TCP Fast Open or QUIC 0-RTT packets is received and the IP-address-based access control is used, the access control does not detect and prohibit HTTP requests conveyed by pack...

CVE-2016-4817

lib/http2/connection.c in H2O before 1.7.3 and 2.x before 2.0.0-beta5 mishandles HTTP/2 disconnection, which allows remote attackers to cause a denial of service (use-after-free and application crash) or possibly execute arbitrary code via a crafted packet.

CVE-2023-50247

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The QUIC stack (quicly), as used by H2O up to commit 43f86e5 (in version 2.3.0-beta and prior), is susceptible to a state exhaustion attack. When H2O is serving HTTP/3, a remote attacker can exploit this vulnerability to progressiv...

CVE-2016-4864

H2O versions 2.0.3 and earlier and 2.1.0-beta2 and earlier allows remote attackers to cause a denial-of-service (DoS) via format string specifiers in a template file via fastcgi, mruby, proxy, redirect or reproxy.