{"id":"CVE-2026-93634","aliases":["EUVD-2026-108974","GHSA-8563-28f8-ph7v"],"status":"published","title":"Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged Shared-File Records","description":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00271,"percentile":0.19717,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-639"],"published":"2026-10-23T13:26:11Z","modified":"2026-11-04T10:47:23Z","products":[{"vendor":"synacor","product":"zimbra_collaboration_suite"},{"vendor":"zimbra","product":"zimbra collaboration suite"}],"references":[{"url":"https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/","tags":["related","Exploit","Third Party Advisory","article"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93634","tags":["advisory"]},{"url":"https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1"},{"url":"https://github.com/advisories/GHSA-8563-28f8-ph7v"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93634.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-93634","title":"Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged Shared-File Records","description":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.","status":"published","published":"2026-10-23T13:26:11.07Z","modified":"2026-10-28T19:50:45.601Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:19:54.122945Z"}],"euvd":[{"id":"EUVD-2026-108974","description":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.","status":"published","published":"2026-10-23T13:26:11Z","modified":"2026-10-28T19:50:45Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T16:59:18.841799Z"}],"ghsa":[{"id":"GHSA-8563-28f8-ph7v","title":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an...","description":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.","status":"published","published":"2026-10-23T15:31:38Z","modified":"2026-10-23T15:31:50Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T15:14:20.113334Z"}],"nvd":[{"id":"CVE-2026-93634","description":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.","status":"published","published":"2026-10-23T14:17:57.263Z","modified":"2026-10-28T21:21:57.463Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:13:03.126833Z"}],"osv":[{"id":"CVE-2026-93634","title":"Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged Shared-File Records","description":"A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.","status":"published","published":"2026-10-23T13:26:11.07Z","modified":"2026-11-08T02:47:43.425171242Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","level":"medium"}],"cwes":["CWE-639"],"updated_at":"2026-11-07T03:08:12.44191Z"}]}}