CVE-2025-52691: SmarterTools SmarterMail · Unrestricted File Upload
Affects SmarterTools SmarterMailSource CVE Database V5
Exploited in the wild · used in ransomware campaigns · KEV due 16 Feb 2026 · public exploit available (Metasploit) · 85% EPSS : apply the vendor's fix or mitigations to SmarterTools SmarterMail now.
Data as of 26 Oct 2026, 06:26 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else.
- Ransomware
- Used in ransomware campaigns
- EPSS
- 85.6% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 29 Dec 2025
Detectable: evidence found.
Weaponised: evidence found.
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 28 days after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by CSA
, 193 days before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, 44 hours after disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed · ransomware use known
, 28 days after disclosure
KEV remediation due
US federal deadline
, 49 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Description
Successful exploitation of the vulnerability could allow an unauthenticated attacker to upload arbitrary files to any location on the mail server, potentially enabling remote code execution.