CVE-2026-34719: Zammad

Medium severity, CVSS 4.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the webhook model was missing a proper validation for loop back addresses, or link-local addresses — only the URL scheme (HTTP/HTTPS) as well as the hostname was checked. This could end up in retrieving confidential metadata of cloud/hosting providers. The existing check is now extended and is applied when configuring webhooks as well as triggering webhook jobs. This vulnerability is fixed in 7.0.1 and 6.5.4.

Affected products

• Zammad Zammad: before 6.5.4 (fixed in 6.5.4); version 7.0.0 only

Published 2026-04-08. Last modified 2026-07-24.