CVE-2020-5921

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: 2020-08-26 · updated 2026-06-17

Description

in BIG-IP versions 15.1.0-15.1.0.4, 15.0.0-15.0.1.3, 14.1.0-14.1.2.6, 13.1.0-13.1.3.4, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.2, Syn flood causes large number of MCPD context messages destined to secondary blades consuming memory leading to MCPD failure. This issue affects only VIPRION hosts with two or more blades installed. Single-blade VIPRION hosts are not affected.

Affected products

F5 BIG-IP APM: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
BIG-IP: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 Big-Ip Analytics: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 Networks, Inc. BIG-IP (AAM): from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
BIG-IP ASM: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 BIG-IP DNS: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 Big-Ip Fraud Protection Service: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 Big-Ip Global Traffic Manager: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 Big-Ip Link Controller: from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 BIG-IP (LTM): from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5
F5 Networks, Inc. BIG-IP (PEM): from 12.1.0 before 12.1.5.2; from 14.1.0 before 14.1.2.7; from 15.0.0 before 15.0.1.4; from 15.1.0 before 15.1.0.5 — fixed in 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5

How to fix

Upgrade to a fixed version: F5 BIG-IP APM 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; BIG-IP 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 Big-Ip Analytics 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 Networks, Inc. BIG-IP (AAM) 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; BIG-IP ASM 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 BIG-IP DNS 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 Big-Ip Fraud Protection Service 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 Big-Ip Global Traffic Manager 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 Big-Ip Link Controller 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 BIG-IP (LTM) 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5; F5 Networks, Inc. BIG-IP (PEM) 12.1.5.2, 14.1.2.7, 15.0.1.4, 15.1.0.5. Check the vendor advisory for mitigations.

References

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