{"id":"CVE-2026-93647","title":"An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address","summary":"An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.","severity":"critical","cvss":9.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","cwe":["CWE-79"],"vendor":"Zimbra","product":"Zimbra Collaboration Suite (ZCS)","affected":["collaboration_suite_zcs < 10.1.21"],"published":"2026-09-25","updated":"2026-09-29","sourceUpdated":"2026-09-29T21:29:07.663","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93647","references":[{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","label":"cve@rapid7.com"}],"tags":["nvd","cve.org"],"epss":0.00229,"epssPercentile":0.1364,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-25T00:00:00+00:00"},"ingestedAt":"2026-09-25T14:09:46.365Z","slug":"CVE-2026-93647","body":"## Overview\n\nAn unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":51,"depthScoreParts":{"impact":51.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}