CVE Catalog

CVE-2025-68624

MediumCVSS 4.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.33%

25th percentile - higher than 25% of all known CVEs

Summary

N-able Mail Assure through April 2026 contains a design-level authorization flaw allowing an authenticated SMTP user to send outbound email using MAIL FROM addresses belonging to other tenants. The server accepts arbitrary sender domains without enforcing domain-to-account binding, so messages pass SPF and DMARC validation. The vendor considers this intended functionality of its shared SMTP relay architecture.

Risk Assessment

An attacker from any tenant can impersonate other tenant domains, enabling phishing and undermining email trust.

Recommendation

Consider restricting sending to your own domains or implementing additional sender verification at the application layer, as the vendor does not plan to change the behavior.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS