CVE-2026-56725 Zammad: Denial of Service via OTRS Import Controller
Unauthenticated attackers can cause denial of service in Zammad by sending requests to an unprotected import endpoint that blocks server workers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56725?
CVE-2026-56725 is a high-severity denial of service vulnerability in zammad, published on 25 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-56725?
How do I fix CVE-2026-56725?
No fix has been published for CVE-2026-56725 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-56725 being exploited?
There is no known exploitation of CVE-2026-56725 in the wild and no public exploit code.
Sources
Also known as GHSA-45cx-9mrq-mmcj.