{"id":"CVE-2026-104083","state":"PUBLISHED","title":"SmarterMail < Build 9777 Stored Mutation XSS via MathML Foreign Content","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.","publishedAt":"2026-10-09T15:06:57.154Z","updatedAt":"2026-10-27T01:30:36.776Z","severity":{"score":5.3,"label":"Medium","version":"4.0","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","source":"VulnCheck"},"assigner":"VulnCheck","products":["Smartertools Smartermail"],"affected":[{"vendor":"Smartertools","product":"Smartermail","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"Build 9777","versionType":"custom"}]}],"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"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/104xxx/CVE-2026-104083.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-104083","state":"PUBLISHED","datePublished":"2026-10-09T15:06:57.154Z","dateUpdated":"2026-10-27T01:30:36.776Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-10-01T18:02:50.084Z"},"containers":{"cna":{"title":"SmarterMail < Build 9777 Stored Mutation XSS via MathML Foreign Content","descriptions":[{"lang":"en","value":"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. 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