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CVE-2025-52691

10.0
Critical
KEV · Exploited in wildEPSS 86%Dec 29, 2025

Unauthenticated file upload on mail server could enable RCE

common questions

Is CVE-2025-52691 being exploited?

Yes. CVE-2025-52691 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.

How severe is CVE-2025-52691?

CVE-2025-52691 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2025-52691?

Not known from our data. No patch reference has been recorded for CVE-2025-52691, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.

What does CVE-2025-52691 affect?

CVE-2025-52691 affects Mail server. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2025-52691?

Patch when available; restrict access to mail servers.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Mail server
impact

Unauthenticated remote code execution via arbitrary file upload on a mail server.

action required

Patch when possible

affected versions
SmarterTools SmarterMail
  • affectedSmarterMail versions Build 9406 and earlier

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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