CVE-2019-25652

SMTP credential theft via unchecked certificate hostname

Published Mar 27, 2026 · Updated Mar 27, 2026

Improper TLS validation in Ubiquiti UniFi Network Controller allows adjacent network attackers to steal SMTP credentials. The controller's SMTP certificate validation accepts a presented certificate without checking that its host identity matches the configured mail server. SMTP mail must be enabled, and an attacker able to intercept the outbound connection can impersonate that server and capture its configured credentials.

CVSS severity7.7
High
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper TLS validation in Ubiquiti UniFi Network Controller allows adjacent network attackers to steal SMTP credentials. The controller's SMTP certificate validation accepts a presented certificate without checking that its host identity matches the configured mail server. SMTP mail must be enabled, and an attacker able to intercept the outbound connection can impersonate that server and capture its configured credentials.

The record

CVE
CVE-2019-25652
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Ubiquiti
Product
UniFi Network Controller
Classifications
CWE-295, T1557
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.10.22
  2. Affected versionversion=5.11 <5.11.18

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Ubiquiti · UniFi Network Controllerversion=0 <5.10.22; version=5.11 <5.11.18

Published CVSS scores

7.7VulnCheckCVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.5VulnCheckCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo