CVE-2026-115786
Zimbra Collaboration Suite Shared-File Mailbox Quota Accounting Error Enables Quota Exhaustion
- State
- Published
- Severity
- 6.5 Medium
- Published
- Oct 23, 2026
- Updated
- Oct 28, 2026
- Reserved
- Oct 23, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | rapid7 |
Weaknesses
- CWE-682 Incorrect Calculation
Affected Products
| Product | Versions |
|---|---|
Zimbra Collaboration SuiteZimbra |
|
References
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