Skip to main content
Apexward Pulse
Type Vulnerability

Dangerous Type

SmarterTools SmarterMail Unrestricted File Upload Vulnerability

1 sourceCVE-2025-52691

At a glance

High
Suggested 24-hour window, counted from the last update
ActiveConfirmed in-the-wild exploitation
Evidence-weighted, not popularity
Signal

Actively exploited in the wild — prioritise confirming exposure.

Why High

High rather than Critical: exposure is scored at a default because we cannot see your systems or suppliers. If you run or depend on SmarterTools SmarterMail, treat it as Critical.

Briefing

  • Do not treat uncorroborated claims as confirmed breaches.

Questions to ask IT

  • Do we run SmarterTools SmarterMail, and which versions?
  • Is any of it reachable from the internet?
  • Have we checked whether it has already been used against us?
  • If it is still not patched, what mitigation is in place, and what is holding the fix up?

Next steps

  1. Confirm exposure, mitigation status and any service interruption risk.

Summary

  • SmarterTools SmarterMail contains an unrestricted upload of file with dangerous type vulnerability that could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.
  • CVE-2025-52691 is listed in known-exploited catalogue (exploitation in the wild)
  • Authoritative catalogues report active exploitation of this vulnerability.

Why this matters in the UK

  • Known-exploited catalogue reports exploitation in the wild

Products and services involved

Pulse

Last checked 4d ago · Recheck overdue since 5 Nov 2026, 22:06 UK time · 4 quiet checks collapsed

Signal
21 Aug 2026, 04:29 UK time · 21 Aug

in the next 30 days first recorded at 85.5% (elevated likelihood signal, not confirmed exploitation).

Elevated — confirm exposure; this is a probability signal, not confirmed exploitation.

EscalationDe-escalationCritical / liveWhat these mean
Drag to pan · Ctrl / ⌘ + scroll or pinch to zoom5 events

2 quiet checks hidden.

Sources

How we know

Statements extracted from sources. Higher confidence means stronger corroboration.

  • ConfirmedHeadline90% confidence

    SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability

  • ConfirmedSummary fact75% confidence

    SmarterTools SmarterMail contains an unrestricted upload of file with dangerous type vulnerability that could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution. Affects SmarterTools SmarterMail. Known ransomware campaign use: Known.

  • ConfirmedCVE identifier95% confidence

    Event involves CVE-2025-52691

  • ConfirmedKnown-exploited catalogue98% confidence

    CVE-2025-52691 is listed in known-exploited catalogue (exploitation in the wild)