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VULNERABILITIES

CVE-2026-115786 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:6.5 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories [email protected]Vendor Advisory
https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ [email protected]Not Applicable

Weakness Enumeration

CWE-IDCWE NameSource
CWE-682Incorrect Calculation[email protected]

Affected Products

ProductVersions
synacor zimbra collaboration suite
<= 10.1.20

CPE

  • cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-115786
NVD Published Date:
Oct 23, 2026
NVD Last Modified:
Nov 2, 2026
Source:
[email protected]