Security readout for executives and security teams
Plain-English summary
Older UniFi Network Controller versions may fail to properly verify SSL certificates when connecting to SMTP servers. An attacker positioned on the same or adjacent network path could impersonate the mail server and capture credentials. This is serious for environments where UniFi uses SMTP accounts for alerts or notifications.
Executive priority
Treat this as a high-priority remediation for environments using UniFi SMTP alerts. The main business risk is theft of mail credentials that may enable broader account abuse, alert disruption, or follow-on access depending on credential scope.
Technical view
CVE-2019-25652 is a CWE-295 improper certificate validation issue in UniFi Network Controller before 5.10.22 and 5.11.x before 5.11.18. During SMTP SSL connections, insufficient host certificate verification can allow adjacent attackers to perform man-in-the-middle interception and credential theft.
Likely exposure
Exposure is most likely in organizations running affected UniFi Network Controller versions with SMTP configured. The attack requires adjacent network positioning or control of the relevant network path, so exposure depends heavily on local network architecture and SMTP routing.
Exploitation context
The source bundle does not report active exploitation, and the CVE is not marked KEV. Exploitation is not described as remote internet exploitation; it requires adjacent network man-in-the-middle capability and a vulnerable controller making SMTP connections.
Researcher notes
The key condition is improper SMTP SSL host verification, not general UniFi device compromise. Validate version ranges and SMTP configuration before escalating. The bundle gives fixed version thresholds but does not provide proof-of-concept details or confirmed exploitation evidence.
Mitigation direction
- Upgrade UniFi Network Controller to 5.10.22, 5.11.18, or later supported versions.
- Review the Ubiquiti advisory for vendor-specific remediation guidance.
- Rotate SMTP credentials used by affected controllers if exposure is suspected.
- Restrict controller-to-SMTP network paths to trusted segments where practical.
Validation and detection
- Inventory UniFi Network Controller versions across managed environments.
- Identify controllers below 5.10.22 or affected 5.11.x releases below 5.11.18.
- Check whether SMTP settings and stored credentials are configured on affected instances.
- Review logs for unexpected SMTP authentication failures or certificate warnings.
- Confirm upgraded controllers retain expected alerting behavior after remediation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-295: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2019-25652 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (4.0)
- Known Exploited
- No
- Published
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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——VulnCheckCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H1.65.9VulnCheckVulnerability scoring details
Base CVSS 4.0 score
7.7HighVector: 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
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://community.ui.com/releases/Security-Advisory-Bulletin-003-003/982bbaa8-2a07-4f81-a5f6-0bb84753f391CVE reference, VulnCheck · vendor-advisory
- https://www.vulncheck.com/advisories/unifi-network-controller-improper-certificate-validation-leading-to-credential-theft-via-mitmCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Certificate Validation
Improper Certificate Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.