Arbitrary file write via upload path traversal
Published Dec 29, 2025 · Updated Dec 29, 2025
Unrestricted file upload in SmarterMail Build 9406 and earlier allows remote attackers to write files anywhere on the mail server. The unauthenticated api/upload endpoint trusts traversal segments in the contextData guid and uses the resulting path for an uploaded part. No credentials or user interaction are required, and a server-executable destination turns the arbitrary file write into remote code execution.
Summary
What happened
Unrestricted file upload in SmarterMail Build 9406 and earlier allows remote attackers to write files anywhere on the mail server. The unauthenticated api/upload endpoint trusts traversal segments in the contextData guid and uses the resulting path for an uploaded part. No credentials or user interaction are required, and a server-executable destination turns the arbitrary file write into remote code execution.
The record
- CVE
- CVE-2025-52691
- Published
- Dec 29, 2025
- Updated
- Dec 29, 2025
- Vendor
- SmarterTools Inc.
- Product
- SmarterMail
- Classifications
- CWE-434, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 29, 2025CVE publishedPublication date reported by the CVE source.
- Dec 29, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=SmarterMail versions Build 9406 and earlier
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- watchTowr SmarterMail detection artifact generatorfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Vulnerabilityknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo