CVE-2026-40077: Beszel has an IDOR in hub API endpoints that read system ID from URL parameter

Severity: low (CVSS 3.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-09 · updated 2026-10-26
Weakness: CWE-184

Description

Beszel is a server monitoring platform. Prior to 0.18.7, some API endpoints in the Beszel hub accept a user-supplied system ID and proceed without further checks that the user should have access to that system. As a result, any authenticated user can access these routes for any system if they know the system's ID. System IDs are random 15 character alphanumeric strings, and are not exposed to all users. However, it is theoretically possible for an authenticated user to enumerate a valid system ID via web API. To use the containers endpoints, the user would also need to enumerate a container ID, which is 12 digit hexadecimal string. This vulnerability is fixed in 0.18.7.

Affected products

henrygd beszel: before 0.18.7 — fixed in 0.18.7

How to fix

Upgrade to a fixed version: henrygd beszel 0.18.7. Check the vendor advisory for mitigations.

References

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