CVE-2019-5456

SMTP MITM refers to a malicious actor setting up an SMTP proxy server between the UniFi...

8.1 High

SMTP MITM refers to a malicious actor setting up an SMTP proxy server between the UniFi Controller version <= 5.10.21 and their actual SMTP server to record their SMTP credentials for malicious use later.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

1.29%Up 0.3 points since Apr 14, 2021

What each source reports

NVD Score used 8.1

Record: CVE-2019-5456
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:P/I:N/A:N
Weakness: CWE-300, CWE-255
Updated: 2026-11-02

CVE List No score

Record: CVE-2019-5456
Weakness: CWE-300
Updated: 2026-11-02

EUVDEUVD-2019-15040 No score

Record: EUVD-2019-15040
Updated: 2026-11-03

GitHub AdvisoriesGHSA-8hq9-mg8q-pw66 8.1

SMTP MITM refers to a malicious actor setting up an SMTP proxy server between the UniFi...

Record: GHSA-8hq9-mg8q-pw66
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

Affected products

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2019-5456 is a high vulnerability (CVSS 8.1) in Ui Unifi Controller, published July 30, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.29%, the 70th percentile. No source names a fixed version.