{"id":"CVE-2026-115786","state":"PUBLISHED","title":"Zimbra Collaboration Suite Shared-File Mailbox Quota Accounting Error Enables Quota Exhaustion","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.","publishedAt":"2026-10-23T13:53:33.918Z","updatedAt":"2026-10-28T19:48:38.750Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"rapid7"},"assigner":"rapid7","products":["Zimbra Zimbra Collaboration Suite"],"affected":[{"vendor":"Zimbra","product":"Zimbra Collaboration Suite","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"10.1.20","versionType":"semver"}]}],"references":["https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories","https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/"],"weaknesses":["CWE-682"],"ingestedAt":"2026-10-29T20:10:43.281Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/115xxx/CVE-2026-115786.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-115786","state":"PUBLISHED","datePublished":"2026-10-23T13:53:33.918Z","dateUpdated":"2026-10-28T19:48:38.750Z","assignerShortName":"rapid7","assignerOrgId":"9974b330-7714-4307-a722-5648477acda7","dateReserved":"2026-10-23T13:41:21.016Z"},"containers":{"cna":{"title":"Zimbra Collaboration Suite Shared-File Mailbox Quota Accounting Error Enables Quota Exhaustion","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Zimbra","product":"Zimbra Collaboration Suite","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"10.1.20","versionType":"semver"}]}],"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-682","lang":"en","description":"CWE-682 Incorrect Calculation","type":"CWE"}]}],"providerMetadata":{"shortName":"rapid7","orgId":"9974b330-7714-4307-a722-5648477acda7","dateUpdated":"2026-10-23T13:53:33.918Z"},"datePublic":"2026-10-23T13:51:00.000Z","credits":[{"lang":"en","value":"Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-28T17:49:33.866375Z","id":"CVE-2026-115786","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-28T19:48:38.750Z"}}]}}}