Some HTTP/2 implementations are vulnerable to a reset flood, potentially leading to a denial of service. The attacker opens a number of streams and sends an invalid request over each stream that should solicit a stream of RST_STREAM frames from the peer. Depending on how the peer queues the RST_STREAM frames, this can consume excess memory, CPU, or both.

Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service. The attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU.

Some HTTP/2 implementations are vulnerable to a flood of empty frames, potentially leading to a denial of service. The attacker sends a stream of frames with an empty payload and without the end-of-stream flag. These frames can be DATA, HEADERS, CONTINUATION and/or PUSH_PROMISE. The peer spends time processing each frame disproportionate to attack bandwidth. This can consume excess CPU.

Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They manipulate 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 can consume excess CPU, memory, or both.

Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The 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.

Simultaneous Multi-threading (SMT) in processors can enable local users to exploit software vulnerable to timing attacks via a side-channel timing attack on 'port contention'.

When BIG-IP 14.0.0-14.0.0.2, 13.0.0-13.1.0.5, 12.1.0-12.1.3.5, 11.6.0-11.6.3.2, or 11.2.1-11.5.6, BIG-IQ Centralized Management 5.0.0-5.4.0 or 4.6.0, BIG-IQ Cloud and Orchestration 1.0.0, iWorkflow 2.1.0-2.3.0, or Enterprise Manager 3.1.1 is licensed for Appliance Mode, Admin and Resource administrator roles can by-pass BIG-IP Appliance Mode restrictions to overwrite critical system files. Attackers of high privilege level are able to overwrite critical system files which bypasses security controls in place to limit TMSH commands. This is possible with an administrator or resource administrator roles when granted TMSH. Resource administrator roles must have TMSH access in order to perform this attack.

On BIG-IP 14.0.0-14.0.0.2, 13.0.0-13.1.0.7, 12.1.0-12.1.3.5, 11.6.0-11.6.3.2, or 11.2.1-11.5.6, BIG-IQ Centralized Management 6.0.0-6.0.1, 5.0.0-5.4.0 or 4.6.0, BIG-IQ Cloud and Orchestration 1.0.0, iWorkflow 2.0.1-2.3.0, or Enterprise Manager 3.1.1 a BIG-IP user granted with tmsh access may cause the BIG-IP system to experience denial-of-service (DoS) when the BIG-IP user uses the tmsh utility to run the edit cli preference command and proceeds to save the changes to another filename repeatedly. This action utilises storage space on the /var partition and when performed repeatedly causes the /var partition to be full.

The OpenSSL ECDSA signature algorithm has been shown to be vulnerable to a timing side channel attack. An attacker could use variations in the signing algorithm to recover the private key. Fixed in OpenSSL 1.1.0j (Affected 1.1.0-1.1.0i). Fixed in OpenSSL 1.1.1a (Affected 1.1.1).

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.