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.
CVSS Score
8.3
EPSS Score
0.0
Published
2026-04-08
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the SSO mechanism in Zammad was not verifying the header originates from a trusted SSO proxy/gateway before applying further actions on it. This vulnerability is fixed in 7.0.1 and 6.5.4.
CVSS Score
2.3
EPSS Score
0.0
Published
2026-04-08
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the OAuth callback endpoints for Microsoft, Google, and Facebook external credentials do not validate a CSRF state parameter. This vulnerability is fixed in 7.0.1 and 6.5.4.
CVSS Score
5.9
EPSS Score
0.0
Published
2026-04-08
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the used endpoint for ticket creation was missing authorization if the related parameter for adding links is used. This vulnerability is fixed in 7.0.1 and 6.5.4.
CVSS Score
6.9
EPSS Score
0.0
Published
2026-04-08
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, unauthenticated remote attackers were able to access the getting started endpoint to get access to sensitive internal entity data, even after the system setup was completed. This vulnerability is fixed in 7.0.1 and 6.5.4.
CVSS Score
8.7
EPSS Score
0.001
Published
2026-04-08
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the REST endpoint POST /api/v1/ai_assistance/text_tools/:id was not checking if a user is privileged to use the text tool, resulting in being able to use it in all situations. This vulnerability is fixed in 7.0.1 and 6.5.4.
CVSS Score
5.3
EPSS Score
0.0
Published
2026-04-08
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the HTML sanitizer for ticket articles was missing proper sanitization of data: ... URI schemes, resulting in storing such malicious content in the database of the Zammad instance. The Zammad GUI is rendering this content, due to applied CSP rules no harm was done by e.g., clicking such a link. This vulnerability is fixed in 7.0.1 and 6.5.4.
CVSS Score
5.3
EPSS Score
0.0
Published
2026-04-08
An issue in Zammad v5.4.0 allows attackers to bypass e-mail verification using an arbitrary address and manipulate the data of the generated user. Attackers are also able to gain unauthorized access to existing tickets.
CVSS Score
6.5
EPSS Score
0.001
Published
2023-05-18
Zammad 5.3.x (Fixed 5.4.0) is vulnerable to Incorrect Access Control. An authenticated attacker could gain information about linked accounts of users involved in their tickets using the Zammad API.
CVSS Score
6.5
EPSS Score
0.003
Published
2023-05-02
Zammad 5.3.x (Fixed in 5.4.0) is vulnerable to Incorrect Access Control. An authenticated attacker with agent and customer roles could perform unauthorized changes on articles where they only have customer permissions.
CVSS Score
6.5
EPSS Score
0.002
Published
2023-05-02
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