---
id: CVE-2025-68624
title: >-
  N-able Mail Assure through April 2026 contains a design-level authorization
  flaw that allows an authenticated SMTP user to send outbound email using MAIL
  FROM addresses belonging to other tenants
summary: >-
  N-able Mail Assure through April 2026 contains a design-level authorization
  flaw that allows an authenticated SMTP user to send outbound email using MAIL
  FROM addresses belonging to other tenants. When connecting to the SMTP TCP
  port and…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-290
vendor: N-able
product: Mail Assure
affected:
  - mail_assure <= April 2026
published: '2026-09-14'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:16:37.937'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-68624'
references:
  - url: 'https://deepsec.net/speaker.html#PSLOT782'
    label: cve@mitre.org
  - url: >-
      https://gist.github.com/alessandrobertoldi/1ebe0f48aa0119d787ac0ff710057d92
    label: cve@mitre.org
  - url: 'https://www.n-able.com/products/mail-assure'
    label: cve@mitre.org
  - url: 'http://seclists.org/fulldisclosure/2026/Jun/10'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/alessandrobertoldi/research/blob/main/infinity-day-at-scale-deepsec2025.pdf
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T16:14:20.384301Z'
epss: 0.00293
epssPercentile: 0.22056
ingestedAt: '2026-09-14T15:23:07.467Z'
---

## Overview

N-able Mail Assure through April 2026 contains a design-level authorization flaw that allows an authenticated SMTP user to send outbound email using MAIL FROM addresses belonging to other tenants. When connecting to the SMTP TCP port and performing SMTP AUTH with valid credentials, the server accepts arbitrary sender domains without enforcing any domain-to-account binding. As a result, an attacker from any tenant can impersonate other tenant domains, producing messages that pass SPF and DMARC validation. NOTE: N-able's position is that the behavior is intended functionality of its shared SMTP relay architecture and that the service does not represent that it enforces per-tenant sender-domain binding.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.