A mailbox quota-accounting vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to consume another user’s mailbox quota by repeatedly sharing and revoking a document. Creation of the recipient’s shared-file record charges the document size to mailbox-wide usage. Revocation deletes the record and reverses its folder counters without reversing the mailbox-wide charge. Repeated normal share notifications therefore accumulate quota usage after the visible records are gone. On accounts with a finite quota, this can prevent incoming mail and other size-increasing operations without recipient interaction. The issue affects ZCS 10.1.16 and 10.1.20.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 7
- StatusUndergoing Analysis → PublishedNVD modified 2026-10-28 19:48
- StatusPublished → Undergoing AnalysisNVD modified 2026-10-28 20:17
- StatusAwaiting Analysis → PublishedNVD modified 2026-10-23 13:53
- StatusPublished → Awaiting AnalysisNVD modified 2026-10-23 16:44
- StatusReceived → PublishedNVD modified 2026-10-23 13:53
- StatusPublished → ReceivedNVD modified 2026-10-23 14:17
- First seenCVSS 6.5 · zimbraNVD modified 2026-10-23 13:53
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.