CVE-2019-6677

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: 2019-12-23 · updated 2026-06-17

Description

On BIG-IP versions 15.0.0-15.0.1, 14.1.0-14.1.2, 14.0.0-14.0.1, 13.1.0-13.1.3.1, and 12.1.0-12.1.5, under certain conditions when using custom TCP congestion control settings in a TCP profile, TMM stops processing traffic when processed by an iRule.

Affected products

F5 BIG-IP APM: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
BIG-IP: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 Big-Ip Analytics: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 Networks, Inc. BIG-IP (AAM): from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
BIG-IP ASM: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 BIG-IP DNS: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 Big-Ip Fraud Protection Service: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 Big-Ip Global Traffic Manager: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 Big-Ip Link Controller: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 BIG-IP (LTM): from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1
F5 Networks, Inc. BIG-IP (PEM): from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.2; from 14.0.0 before 14.0.1.1; from 14.1.0 before 14.1.2.1; from 15.0.0 before 15.0.1.1 — fixed in 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1

How to fix

Upgrade to a fixed version: F5 BIG-IP APM 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; BIG-IP 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 Big-Ip Analytics 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 Networks, Inc. BIG-IP (AAM) 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; BIG-IP ASM 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 BIG-IP DNS 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 Big-Ip Fraud Protection Service 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 Big-Ip Global Traffic Manager 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 Big-Ip Link Controller 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 BIG-IP (LTM) 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1; F5 Networks, Inc. BIG-IP (PEM) 13.1.3.2, 14.0.1.1, 14.1.2.1, 15.0.1.1. Check the vendor advisory for mitigations.

References

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