Zammad: Cross-User Taskbar Item Access Control Vulnerability

{
  "id": "7e7e1cefc45d32a63a7d343fef07bf2b16fe8bb39b1f230b9384e89dc505f58b",
  "url": "https://osv.dev/vulnerability/CVE-2026-56728",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Zammad: Cross-User Taskbar Item Access Control Vulnerability",
    "summary": "Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, a broken access control vulnerability exists in Zammad's GraphQL API. An authenticated user can access taskbar item data belonging to another user by crafting a request with the target user's taskbar identifier. The taskbar feature stores transient state for active user sessions, including auto-saved ticket drafts. Under certain conditions, the authorization check for taskbar item access is not enforced, allowing a user to read another user's taskbar item data. This vulnerability is fixed in 7.0.2.",
    "evidence": "osv:CVE-2026-56728",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-56728",
      "aliases": [
        "CVE-2026-56728",
        "GHSA-jvcg-5539-vvc3"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zammad/zammad",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9dc15acf239dbc32ec357708859f2d86b188846c"
                },
                {
                  "fixed": "4ccd5d573023b66b0d0184914c92417e1780793f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "7.0.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4ccd5d573023b66b0d0184914c92417e1780793f"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "9dc15acf239dbc32ec357708859f2d86b188846c"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "7.0.2"
                  }
                ]
              }
            }
          ],
          "versions": [
            "7.0.1",
            "7.0.0",
            "7.0.0-alpha",
            "6.6.0-alpha",
            "6.5.0-alpha",
            "6.4.0-alpha",
            "6.3.0-alpha",
            "6.2.0-alpha",
            "6.1.0-alpha",
            "6.0.0-alpha",
            "5.5.0-alpha",
            "5.4.0-alpha",
            "5.3.0-alpha",
            "5.2.0-alpha",
            "3.7.0",
            "1.6.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56728.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:39.721423119Z",
      "provider": "osv",
      "references": [
        "https://github.com/zammad/zammad/releases/tag/7.0.2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56728.json",
        "https://github.com/zammad/zammad/security/advisories/GHSA-jvcg-5539-vvc3",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-56728",
        "https://github.com/zammad/zammad/commit/4ccd5d573023b66b0d0184914c92417e1780793f"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-200",
          "CWE-639"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56728.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-56728",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 507155,
  "published_at": "2026-09-25T17:10:16.262+00:00"
}