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Zammad: Denial of Service via OTRS Import Controller

Type: advisorySources: OSV

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, summary An unauthenticated request to POST /api/v1/import/otrs/import_check blocks a Zammad request worker for roughly two minutes. The import_check and import_status actions are missing the setup_done_response guard that other actions in the same controller carry, so they execute on fully set-up production instances. The action enters a retry loop against a blank OTRS endpoint, sleeping for 30 s + 45 s between attempts. Impact An unauthenticated remote attacker denies service to a production Zammad instance. Each request costs almost nothing and forces ~115 seconds of server-side blocking. A few requests per second saturate the Puma worker pool. The condition persists as long as the traffic continues. No account, valid import configuration, or target knowledge beyond the hostname is needed. CSRF token is trivially obtained from any prior GET response. This issue is fixed in version 7.0.2.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-56725
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 02:47 UTC · Revision 1

Source evidence

Zammad: Denial of Service via OTRS Import Controller

core-osv · Original source

Published 25 Sept 2026, 17:09 UTC

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, summary An unauthenticated request to POST /api/v1/import/otrs/import_check blocks a Zammad request worker for roughly two minutes. The import_check and import_status actions are missing the setup_done_response guard that other actions in the same controller carry, so they execute on fully set-up production instances. The action enters a retry loop against a blank OTRS endpoint, sleeping for 30 s + 45 s between attempts. Impact An unauthenticated remote attacker denies service to a production Zammad instance. Each request costs almost nothing and forces ~115 seconds of server-side blocking. A few requests per second saturate the Puma worker pool. The condition persists as long as the traffic continues. No account, valid import configuration, or target knowledge beyond the hostname is needed. CSRF token is trivially obtained from any prior GET response. This issue is fixed in version 7.0.2.

osv:CVE-2026-56725
Complete source record
{
  "id": "09976bc4d6e1df85f0f7eec087d18d587dae4fce974e5e7a996188eb960423f4",
  "url": "https://osv.dev/vulnerability/CVE-2026-56725",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Zammad: Denial of Service via OTRS Import Controller",
    "summary": "Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, summary An unauthenticated request to POST /api/v1/import/otrs/import_check blocks a Zammad request worker for roughly two minutes. The import_check and import_status actions are missing the setup_done_response guard that other actions in the same controller carry, so they execute on fully set-up production instances. The action enters a retry loop against a blank OTRS endpoint, sleeping for 30 s + 45 s between attempts. Impact An unauthenticated remote attacker denies service to a production Zammad instance. Each request costs almost nothing and forces ~115 seconds of server-side blocking. A few requests per second saturate the Puma worker pool. The condition persists as long as the traffic continues. No account, valid import configuration, or target knowledge beyond the hostname is needed. CSRF token is trivially obtained from any prior GET response. This issue is fixed in version 7.0.2.",
    "evidence": "osv:CVE-2026-56725",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-56725",
      "aliases": [
        "CVE-2026-56725",
        "GHSA-45cx-9mrq-mmcj"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zammad/zammad",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9dc15acf239dbc32ec357708859f2d86b188846c"
                },
                {
                  "fixed": "a04a95b69496306af4c1fbd369a54981122e67c0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "7.0.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a04a95b69496306af4c1fbd369a54981122e67c0"
                      }
                    ],
                    "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-2026-56725.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.470799475Z",
      "provider": "osv",
      "references": [
        "https://github.com/zammad/zammad/releases/tag/7.0.2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56725.json",
        "https://github.com/zammad/zammad/security/advisories/GHSA-45cx-9mrq-mmcj",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-56725",
        "https://github.com/zammad/zammad/commit/a04a95b69496306af4c1fbd369a54981122e67c0"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-306",
          "CWE-400"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56725.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-56725",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491989,
  "published_at": "2026-09-25T17:09:05.633+00:00"
}