{"id":"CVE-2026-93631","title":"Zimbra Collaboration Suite OAuth Extension Cross-Site Request Forgery Enables Account Linking","summary":"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 b…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N","cvssSource":"cna","cwe":["CWE-352"],"vendor":"Zimbra","product":"Zimbra Collaboration Suite","affected":["collaboration_suite <= 10.1.20"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T13:23:34.952Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93631","references":[{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories"},{"url":"https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T14:28:08.712Z","slug":"CVE-2026-93631","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `collaboration_suite <= 10.1.20`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}