SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerability
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.
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 5 / 5
- KEV catalog (CISA)26 Jan 2026
- Exploited in EUVD (ENISA)26 Jan 2026
- Used by ransomwareyes
- EPSS above 10 %85.7%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Affected products
- SmarterMail versions Build 9406 and earlier
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
-
EPSS peak: 85.7%
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-24423SmarterTools SmarterMail Missing Authentication for Critical Function Vulnerability9.4 · Background exploitation
- CVE-2026-23760SmarterTools SmarterMail Authentication Bypass Using an Alternate Path or Channel Vulnerability9.6 · Background exploitation