{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-115786", "assignerOrgId": "9974b330-7714-4307-a722-5648477acda7", "state": "PUBLISHED", "assignerShortName": "rapid7", "dateReserved": "2026-10-23T13:41:21.016Z", "datePublished": "2026-10-23T13:53:33.918Z", "dateUpdated": "2026-10-23T13:53:33.918Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "9974b330-7714-4307-a722-5648477acda7", "shortName": "rapid7", "dateUpdated": "2026-10-23T13:53:33.918Z"}, "title": "Zimbra Collaboration Suite Shared-File Mailbox Quota Accounting Error Enables Quota Exhaustion", "datePublic": "2026-10-23T13:51:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-682", "description": "CWE-682 Incorrect Calculation", "type": "CWE"}]}], "affected": [{"vendor": "Zimbra", "product": "Zimbra Collaboration Suite", "versions": [{"status": "affected", "version": "0", "lessThanOrEqual": "10.1.20", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "A mailbox quota-accounting vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to consume another user\u2019s mailbox quota by repeatedly sharing and revoking a document. Creation of the recipient\u2019s 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.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "A mailbox quota-accounting vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to consume another user\u2019s mailbox quota by repeatedly sharing and revoking a document. Creation of the recipient\u2019s 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."}]}], "references": [{"url": "https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories", "tags": ["vendor-advisory"]}, {"url": "https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/", "tags": ["related"]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH", "baseSeverity": "MEDIUM", "baseScore": 6.5, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}}], "credits": [{"lang": "en", "value": "Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7", "type": "finder"}], "source": {"discovery": "UNKNOWN"}, "x_generator": {"engine": "Vulnogram 1.0.5"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Zimbra Collaboration Suite", "vendor": "Zimbra", "versions": [{"lessThanOrEqual": "10.1.20", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "cve@rapid7.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "A mailbox quota-accounting vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to consume another user\u2019s mailbox quota by repeatedly sharing and revoking a document. Creation of the recipient\u2019s 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."}], "id": "CVE-2026-115786", "lastModified": "2026-10-23T14:17:52.867", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "cve@rapid7.com", "type": "Secondary"}]}, "published": "2026-10-23T14:17:52.867", "references": [{"source": "cve@rapid7.com", "url": "https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories"}, {"source": "cve@rapid7.com", "url": "https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"}], "sourceIdentifier": "cve@rapid7.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-682"}], "source": "cve@rapid7.com", "type": "Secondary"}]}

{}

{"created": "2026-10-23T16:00:18.681603+00:00", "updated": "2026-10-23T16:00:18.681608+00:00", "vendors": []}