CVE-2026-61525: Zammad: Arbitrary File Deletion via Unvalidated Session Identifier in Long Polling Controller
Zammad is a web based open source helpdesk/customer support system. In 7.0.2 and 7.1.0, zammad's session management for websocket and long-polling connections is susceptible to a path traversal attack. Session identifiers supplied by the client are insufficiently validated before being used to construct internal file paths. When the file-based session store is active (the default configuration), an authenticated attacker can manipulate the session identifier to reference locations outside the intended storage directory, leading to the deletion of arbitrary files and directories on the server. Exploitation requires only a low-privilege authenticated session and a single crafted request. Instances configured to use the Redis-based session store are not affected. This issue is fixed in versions 7.0.3 and 7.1.1.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Zammadto a version that resolves this vulnerability.Fixed in 7.0.3 - Upgrade
Upgrade
Zammadto a version that resolves this vulnerability.Fixed in 7.1.1
Event History
Frequently Asked Questions
Which deployments are affected?
Instances running Zammad 7.0.2 or 7.1.0 with the file-based session store active are affected. The file-based store is the default configuration; deployments using the Redis-based session store are not affected.
What access does an attacker need?
An attacker needs a low-privilege authenticated Zammad session. Exploitation requires a single crafted request containing a manipulated session identifier.
What can an attacker do through this issue?
The manipulated session identifier can cause internal paths to resolve outside the intended session-storage directory. This can lead to deletion of arbitrary files and directories on the server.
What should be done if an update cannot be applied immediately?
Configure the instance to use the Redis-based session store, which is not affected by this issue. Update affected 7.0.2 installations to 7.0.3 and affected 7.1.0 installations to 7.1.1 when possible.