{"id":"CVE-2026-93631","aliases":[],"title":"Zimbra Collaboration Suite OAuth Extension Cross-Site Request Forgery Enables Account Linking","titleSource":"rapid7","descriptionSource":"rapid7","products":[{"vendor":"Zimbra","name":"Zimbra Collaboration Suite","platforms":[],"versions":[{"version":"0","status":"affected","lessThanOrEqual":"10.1.20","versionType":"semver"}],"defaultStatus":"unaffected","source":"rapid7","url":"https://www.cve.org/CVERecord?id=CVE-2026-93631"}],"remediation":[],"description":"A cross-site request forgery vulnerability in the OAuth extension of Zimbra Collaboration Suite (ZCS) Network Edition allows an attacker to link an attacker-controlled external account to a victim's mailbox. The OAuth callback does not bind its state value or authorization code to the initiating Zimbra session and instead selects the destination mailbox from the browser's current authentication cookie. On a deployment with the provider configured, an attacker can induce a signed-in victim to load a callback containing a fresh code for the attacker's provider account. This creates a persistent data source that imports attacker-controlled contacts or events. With bidirectional CalDAV synchronization, appointments subsequently created or edited in the linked calendar are also disclosed to the attacker. ZCS 10.1.16 and 10.1.20 are affected.","severity":"high","score":7.1,"published":"2026-10-23T13:23:34.952Z","modified":"2026-10-28T19:51:18.814Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"],"sources":[{"name":"CVE","id":"CVE-2026-93631","modified":"2026-10-28T19:51:18.814Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-93631"}],"assessments":[{"source":"rapid7","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N","score":7.1}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-29T04:55:31.812Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}