{"id":"CVE-2026-104083","aliases":[],"title":"SmarterMail < Build 9777 Stored Mutation XSS via MathML Foreign Content","titleSource":"VulnCheck","descriptionSource":"VulnCheck","products":[{"vendor":"Smartertools","name":"Smartermail","platforms":[],"versions":[{"version":"0","status":"affected","lessThan":"Build 9777","versionType":"custom"}],"defaultStatus":"unaffected","source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-104083"}],"remediation":[],"description":"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.","severity":"medium","score":5.3,"published":"2026-10-09T15:06:57.154Z","modified":"2026-10-27T01:30:36.776Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://www.smartertools.com/smartermail/release-notes/current#/9526:~:text=Build%209777%20(Oct%208%2C%202026)","https://blog.evan.lat/posts/sm/","https://www.vulncheck.com/advisories/smartermail-build-9777-stored-mutation-xss-via-mathml-foreign-content"],"sources":[{"name":"CVE","id":"CVE-2026-104083","modified":"2026-10-27T01:30:36.776Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-104083"}],"assessments":[{"source":"VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","score":5.3},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T17:55:31.619Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}