What’s Vulnerable › Vulnerabilities

CVE-2020-27720

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-12-24 · updated 2026-06-17

Description

On BIG-IP LTM/CGNAT version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, and 13.1.0-13.1.3.5, when processing NAT66 traffic with Port Block Allocation (PBA) mode and SP-DAG enabled, and dag-ipv6-prefix-len configured with a value less than the default of 128, an undisclosed traffic pattern may cause the Traffic Management Microkernel (TMM) to restart.

Affected products

• F5 Big-Ip Carrier-Grade Nat: from 13.1.0 through 13.1.3; from 14.1.0 before 14.1.3.1; from 15.1.0 before 15.1.1; from 16.0.0 before 16.0.1 — fixed in 14.1.3.1, 15.1.1, 16.0.1
• F5 BIG-IP (LTM): from 13.1.0 through 13.1.3; from 14.1.0 before 14.1.3.1; from 15.1.0 before 15.1.1; from 16.0.0 before 16.0.1 — fixed in 14.1.3.1, 15.1.1, 16.0.1

How to fix

Upgrade to a fixed version: F5 Big-Ip Carrier-Grade Nat 14.1.3.1, 15.1.1, 16.0.1; F5 BIG-IP (LTM) 14.1.3.1, 15.1.1, 16.0.1. Check the vendor advisory for mitigations.

References

• https://support.f5.com/csp/article/K04048104
• https://support.f5.com/csp/article/K04048104

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