CVE-2020-5923: 
F5 BIG-IP Advanced Firewall Manager vulnerability analysis and mitigation

CVE-2020-5923 is a security vulnerability affecting F5's BIG-IP and BIG-IQ products. The vulnerability was discovered in early 2020 and involves a Self-IP port-lockdown bypass via IPv6 link-local addresses. The affected versions include BIG-IP versions 15.0.0-15.1.0.4, 14.1.0-14.1.2.6, 13.1.0-13.1.3.3, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.1, as well as BIG-IQ versions 5.4.0-7.0.0 (CVE Mitre).

The vulnerability has been assigned a CVSS score of 5.0 (AV:A/AC:L/Au:N/C:P/I:P/A:N), indicating a medium severity level. The attack requires adjacent network access, has low attack complexity, requires no authentication, and can result in partial confidentiality and integrity impacts (Rapid7).

The vulnerability can lead to a bypass of security controls, specifically the Self-IP port-lockdown feature, through IPv6 link-local addresses. This could potentially allow attackers with adjacent network access to bypass intended network security restrictions (CVE Mitre).

The vulnerability requires adjacent network access to exploit, meaning an attacker would need to be on the same network segment as the targeted system. The attack complexity is considered low, indicating that the vulnerability is relatively straightforward to exploit once access is obtained (Rapid7).

F5 has released patches for the affected versions. Users are advised to upgrade to the following fixed versions: 11.6.5.2, 12.1.5.2, 13.1.3.4, 14.1.3.1, 15.1.1, or 16.0.1 (CERT-FR).