CVE-2021-22999

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-31 · updated 2026-06-17

Description

On versions 15.0.x before 15.1.0 and 14.1.x before 14.1.4, the BIG-IP system provides an option to connect HTTP/2 clients to HTTP/1.x servers. When a client is slow to accept responses and it closes a connection prematurely, the BIG-IP system may indefinitely retain some streams unclosed. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

Affected products

F5 BIG-IP APM: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
BIG-IP: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Big-Ip Advanced Web Application Firewall: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Big-Ip Analytics: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Networks, Inc. BIG-IP (AAM): from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
BIG-IP ASM: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Big-Ip Ddos Hybrid Defender: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 BIG-IP DNS: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Big-Ip Fraud Protection Service: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Big-Ip Global Traffic Manager: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Big-Ip Link Controller: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 BIG-IP (LTM): from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 Networks, Inc. BIG-IP (PEM): from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0
F5 SSL Orchestrator: from 14.1.0 before 14.1.4; from 15.0.0 before 15.1.0 — fixed in 14.1.4, 15.1.0

How to fix

Upgrade to a fixed version: F5 BIG-IP APM 14.1.4, 15.1.0; BIG-IP 14.1.4, 15.1.0; F5 Big-Ip Advanced Web Application Firewall 14.1.4, 15.1.0; F5 Big-Ip Analytics 14.1.4, 15.1.0; F5 Networks, Inc. BIG-IP (AAM) 14.1.4, 15.1.0; BIG-IP ASM 14.1.4, 15.1.0; F5 Big-Ip Ddos Hybrid Defender 14.1.4, 15.1.0; F5 BIG-IP DNS 14.1.4, 15.1.0; F5 Big-Ip Fraud Protection Service 14.1.4, 15.1.0; F5 Big-Ip Global Traffic Manager 14.1.4, 15.1.0; F5 Big-Ip Link Controller 14.1.4, 15.1.0; F5 BIG-IP (LTM) 14.1.4, 15.1.0. Check the vendor advisory for mitigations.

References

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