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.

The Apache HTTP Server 1.x and 2.x allows remote attackers to cause a denial of service (daemon outage) via partial HTTP requests, as demonstrated by Slowloris, related to the lack of the mod_reqtimeout module in versions before 2.2.15.

Memory leak in the apr_brigade_split_line function in buckets/apr_brigade.c in the Apache Portable Runtime Utility library (aka APR-util) before 1.3.10, as used in the mod_reqtimeout module in the Apache HTTP Server and other software, allows remote attackers to cause a denial of service (memory consumption) via unspecified vectors related to the destruction of an APR bucket.

Integer overflow in the ap_proxy_send_fb function in proxy/proxy_util.c in mod_proxy in the Apache HTTP Server before 1.3.42 on 64-bit platforms allows remote origin servers to cause a denial of service (daemon crash) or possibly execute arbitrary code via a large chunk size that triggers a heap-based buffer overflow.

The apr_strmatch_precompile function in strmatch/apr_strmatch.c in Apache APR-util before 1.3.5 allows remote attackers to cause a denial of service (daemon crash) via crafted input involving (1) a .htaccess file used with the Apache HTTP Server, (2) the SVNMasterURI directive in the mod_dav_svn module in the Apache HTTP Server, (3) the mod_apreq2 module for the Apache HTTP Server, or (4) an application that uses the libapreq2 library, which triggers a heap-based buffer underflow.

PHP 4.3.4 and earlier in Apache 1.x and 2.x (mod_php) can leak global variables between virtual hosts that are handled by the same Apache child process but have different settings, which could allow remote attackers to obtain sensitive information.

Directory traversal vulnerability in Apache 1.3.29 and earlier, and Apache 2.0.48 and earlier, when running on Cygwin, allows remote attackers to read arbitrary files via a URL containing "..%5C" (dot dot encoded backslash) sequences.

SmallHTTP 1.204 through 3.00 beta 8 allows remote attackers to cause a denial of service via multiple long URL requests.

LocalWEB HTTP server 1.2.0 allows remote attackers to cause a denial of service via a long GET request.

Small HTTP Server ver 3.06 contains a memory corruption bug causing a memory overflow. The overflowed buffer crashes into a Structured Exception Handler resulting in a Denial of Service.