Path Traversal in Beszel
CVE-2026-27734
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.
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 0.005 (39.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Beszel
- Henrygd Beszel — versions < 0.18.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-27734?
- CVE-2026-27734 is a medium-severity vulnerability in Beszel, classified under Path Traversal. CVSS score: 6.5/10. Published 2026-02-27.
- How severe is CVE-2026-27734?
- Medium severity. CVSS v3 base score is 6.5 out of 10.