← Back to CVE Explorer

CVE-2026-93627

Full vulnerability record from the local CVENow database.

Description

An organizer authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to cancel or modify an existing meeting in a recipient's calendar. Zimbra accepts iCalendar CANCEL and REQUEST components without verifying that the email sender is authorized to act as the supplied organizer. An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details. Processing occurs automatically during email delivery without recipient interaction. ZCS 10.1.16 and 10.1.21 are affected.

Severity
MEDIUM
CVSS score
5.3 (v3.1)
Vulnerability status
Undergoing Analysis
Source identifier
Published
2026-10-23 14:17:56.547000
Last modified
2026-10-28 20:18:52
View original CVE JSON
{
  "id": "CVE-2026-93627",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-23T14:17:56.547",
  "lastModified": "2026-10-28T20:18:52.000",
  "vulnStatus": "Undergoing Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An organizer authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to cancel or modify an existing meeting in a recipient's calendar. Zimbra accepts iCalendar CANCEL and REQUEST components without verifying that the email sender is authorized to act as the supplied organizer. An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details. Processing occurs automatically during email delivery without recipient interaction. ZCS 10.1.16 and 10.1.21 are affected."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Zimbra",
          "product": "Zimbra Collaboration Suite",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "lessThanOrEqual": "10.1.21",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-28T18:23:52.328566Z",
          "id": "CVE-2026-93627",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-290"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories",
      "source": "[email protected]"
    },
    {
      "url": "https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/",
      "source": "[email protected]"
    }
  ]
}