CVE-2026-115786Zimbra Collaboration Suite Shared-File Mailbox Quota Accounting Error Enables Quota Exhaustion
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-682
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- rapid7
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 23, 2026
- First seen by InfoSec Signals
- Oct 23, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.