UniFi Network Controller before version 5.10.22 and 5.11.x before 5.11.18 contains an improper certificate verification vulnerability that allows adjacent network attackers to conduct man-in-the-middle attacks by presenting a false SSL certificate during SMTP connections. Attackers can intercept SMTP traffic and obtain credentials by exploiting the insecure SSL host verification mechanism in the SMTP certificate validation process.
Published: 2026-03-27
Updated: 2026-03-27
Base Score: 6.8
Vector: CVSS2#AV:A/AC:H/Au:N/C:C/I:C/A:C
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 7.7
Vector: CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: High