In Zammad 6.4.x before 6.4.2, there is information exposure. Only agents should be able to see and work on shared article drafts. However, a logged in customer was able to see details about shared drafts for their customer tickets in the browser console, which may contain confidential information, and also to manipulate them via API.

An issue in the component /api/v1/mentions of Zammad v5.3.0 allows authenticated attackers with agent permissions to view information about tickets they are not authorized to see.

A vulnerability in Zammad v5.3.0 allows attackers to execute arbitrary code or escalate privileges via a crafted message sent to the server.

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.

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.

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.

An issue was discovered in Zammad before 6.2.0. When listing tickets linked to a knowledge base answer, or knowledge base answers of a ticket, a user could see entries for which they lack permissions.

An issue was discovered in Zammad before 6.2.0. Due to lack of rate limiting in the "email address verification" feature, an attacker could send many requests for a known address to cause Denial Of Service (generation of many emails, which would also spam the victim).

An issue was discovered in Zammad before 6.2.0. In several subsystems, SSL/TLS was used to establish connections to external services without proper validation of hostname and certificate authority. This is exploitable by man-in-the-middle attackers.

An issue was discovered in Zammad before 6.2.0. It uses the public endpoint /api/v1/signshow for its login screen. This endpoint returns internal configuration data of user object attributes, such as selectable values, which should not be visible to the public.

Insufficient privilege verification in Zammad v5.3.0 allows an authenticated attacker to perform changes on the tags of their customer tickets using the Zammad API. This is now corrected in v5.3.1 so that only agents with write permissions may change ticket tags.

Zammad 5.2.0 is vulnerable to privilege escalation. Zammad has a prevention against brute-force attacks trying to guess login credentials. After a configurable amount of attempts, users are invalidated and logins prevented. An attacker might work around this prevention, enabling them to send more than the configured amount of requests before the user invalidation takes place.

In Zammad 5.2.0, customers who have secondary organizations assigned were able to see all organizations of the system rather than only those to which they are assigned.

In Zammad 5.2.0, an attacker could manipulate the rate limiting in the 'forgot password' feature of Zammad, and thereby send many requests for a known account to cause Denial Of Service by many generated emails which would also spam the victim.

Zammad 5.2.0 suffers from Incorrect Access Control. Zammad did not correctly perform authorization on certain attachment endpoints. This could be abused by an unauthenticated attacker to gain access to attachments, such as emails or attached files.

A lack of rate limiting in the 'forgot password' feature of Zammad v5.1.0 allows attackers to send an excessive amount of reset requests for a legitimate user, leading to a possible Denial of Service (DoS) via a large amount of generated e-mail messages.

A lack of password length restriction in Zammad v5.1.0 allows for the creation of extremely long passwords which can cause a Denial of Service (DoS) during password verification.

An access control issue in Zammad v5.0.3 allows attackers to write entries to the CTI caller log without authentication. This vulnerability can allow attackers to execute phishing attacks or cause a Denial of Service (DoS).

An access control issue in Zammad v5.0.3 broadcasts administrative configuration changes to all users who have an active application instance, including settings that should only be visible to authenticated users.

In Zammad 5.0.2, agents can configure "out of office" periods and substitute persons. If the substitute persons didn't have the same permissions as the original agent, they could receive ticket notifications for tickets that they have no access to.