Cross-tenant domain impersonation via unchecked SMTP sender
Published Sep 14, 2026 · Updated Sep 14, 2026
Authorization bypass in N-able Mail Assure through April 2026 allows remote authenticated users to impersonate other tenant domains. The SMTP submission path accepts arbitrary MAIL FROM domains after SMTP AUTH without checking that the authenticated account controls the sender domain. Valid tenant credentials and an independently onboarded target domain are required; forged messages pass SPF and DMARC, although N-able calls the behavior intended.
Summary
What happened
Authorization bypass in N-able Mail Assure through April 2026 allows remote authenticated users to impersonate other tenant domains. The SMTP submission path accepts arbitrary MAIL FROM domains after SMTP AUTH without checking that the authenticated account controls the sender domain. Valid tenant credentials and an independently onboarded target domain are required; forged messages pass SPF and DMARC, although N-able calls the behavior intended.
The record
- CVE
- CVE-2025-68624
- Published
- Sep 14, 2026
- Updated
- Sep 14, 2026
- Vendor
- N-able
- Product
- Mail Assure
- Classifications
- CWE-290, T1036
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 14, 2026CVE publishedPublication date reported by the CVE source.
- Sep 14, 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.
- Affected versionversion=0 <=April 2026
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- Infinity-Day at Scale SMTP spoofing proof of conceptproof of concept · demonstrated
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