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CVE-2026-104083

SmarterMail < Build 9777 Stored Mutation XSS via MathML Foreign Content

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in Build 9777
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

SmarterMail before build 9777 contains a stored mutation cross-site scripting vulnerability that allows remote attackers to inject executable script by placing payloads inside a <style> element nested within MathML foreign content (<math><mtext><mglyph>), which the custom HTML sanitizer treats as inert CDATA text but browsers reparse as live markup. Attackers can deliver a crafted calendar (iCal) message containing an <img src=x onerror=...> payload that executes automatically in the recipient's webmail session at /interface/message-iframe when the message is opened, enabling script execution and data exfiltration unconstrained by the interface's permissive Content-Security-Policy.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Smartertools Smartermail

    fixed in Build 9777

References 3

smartertools.com

blog.evan.lat

vulncheck.com