A flaw was found in HTTP/2. An attacker can request a large amount of data by manipulating window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this queue can consume excess CPU, memory, or both, leading to a denial of service. The highest threat from this vulnerability is to system availability.
A vulnerability was found in http/2 where an attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both, potentially leading to a denial of service.
A flaw was found in HTTP/2. Using frames with an empty payload, a flood could occur that results in excessive CPU usage and starvation of other clients. The highest threat from this vulnerability is to system availability.
A flaw was found in HTTP/2. Using SETTINGS frames and queuing of SETTINGS ACK frames, a flood could occur resulting in unbounded memory growth. The highest threat from this vulnerability is to system availability.
A flaw was found in HTTP/2. Using HEADER frames with invalid HTTP headers and queuing of response RSTSTREAM frames, an attacker could cause a flood resulting in unbounded memory growth. The highest threat from this vulnerability is to system availability.
A flaw was found in HTTP/2. An attacker, using PRIORITY frames to flood the system, could cause excessive CPU usage and starvation of other clients. The largest threat from this vulnerability is to system availability.
Apache HTTP Server, with MPM event, worker or prefork, code executing in less-privileged child processes or threads (including scripts executed by an in-process scripting interpreter) could execute code with the privileges of the parent process (usually root) by manipulating the scoreboard.
Apache httpd before version 2.4.34 has a vulnerability in the handling of specially crafted HTTP/2 requests, causing workers to be allocated 60 seconds longer than necessary, leading to worker exhaustion and a denial of service.
This issue only affects servers that have configured and enabled HTTP/2 support, which is not the default
External References:
https://httpd.apache.org/security/vulnerabilities24.html#CVE-2018-1333
APR. Multiple issues in Perl were addressed with improved memory handling.
Apache HTTP Server, in all releases prior to 2.2.32 and 2.4.25, was liberal in the whitespace accepted from requests and sent in response lines and headers. Accepting these different behaviors represented a security concern when httpd participates in any chain of proxies or interacts with back-end application servers, either through modproxy or using conventional CGI mechanisms, and may result in request smuggling, response splitting and cache pollution.
apache. Multiple issues existed in Apache. These were addressed by updating Apache to version 2.4.25.