Clearswift MAILsweeper for SMTP before 4.3.20 and MAILsweeper for Exchange before 4.3.20 allows remote attackers to cause a denial of service via (1) non-ASCII characters in a reverse DNS lookup result from a Received header, which leads to a Receiver service stop, and (2) unspecified vectors involving malformed messages, which causes "unpredictable behavior" that prevents the Security service from processing more messages.
Conclusion & alert: CVE-2006-3216 is rated Moderate Risk (47.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.82%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 1.29% | 1.82% | +0.53% |
| 2 | 2025-03-30 | 1.22% | 1.29% | +0.08% |
| 3 | 2025-03-29 | — | 1.22% | — |
Full EPSS history (11 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
: This vulnerability is addressed in the following product releases: Clearswift, MAILsweeper for SMTP, 4.3.20 Clearswift, MAILsweeper for Exchange, 4.3.20
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| clearswift | mailsweeper_for_exchange | <= 4.3.19 | cpe:2.3:a:clearswift:mailsweeper_for_exchange:*:*:*:*:*:*:*:* |
| clearswift | mailsweeper_for_smtp | <= 4.3.19 | cpe:2.3:a:clearswift:mailsweeper_for_smtp:*:*:*:*:*:*:*:* |