henrygd beszel up to 0.18.3 API Endpoint logs PathEscape path traversal

Summaryinfo

A vulnerability labeled as critical has been found in henrygd beszel up to 0.18.3. This affects the function PathEscape of the file /api/beszel/containers/logs of the component API Endpoint. Such manipulation leads to path traversal. This vulnerability is listed as CVE-2026-27734. The attack may be performed from remote. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in henrygd beszel up to 0.18.3. It has been rated as critical. Affected by this issue is the function PathEscape of the file /api/beszel/containers/logs of the component API Endpoint. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality. CVE summarizes:

Beszel is a server monitoring platform. Prior to version 0.18.2, the hub's authenticated API endpoints GET /api/beszel/containers/logs and GET /api/beszel/containers/info pass the user-supplied "container" query parameter to the agent without validation. The agent constructs Docker Engine API URLs using fmt.Sprintf with the raw value instead of url.PathEscape(). Since Go's http.Client does not sanitize `../` sequences from URL paths sent over unix sockets, an authenticated user (including readonly role) can traverse to arbitrary Docker API endpoints on agent hosts, exposing sensitive infrastructure details. Version 0.18.4 fixes the issue.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-27734 since 02/23/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

Upgrading to version 0.18.4 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-9053). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• henrygd

Name

• beszel

Version

• 0.18.0
• 0.18.1
• 0.18.2
• 0.18.3

Website

• Product: https://github.com/henrygd/beszel/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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