Description
Beszel before 0.19.0 contains an insecure direct object reference vulnerability in the POST and DELETE /api/beszel/user-alerts handlers that allows any authenticated user to create or delete alerts on systems they cannot access. Attackers can supply arbitrary system IDs in the request body to register alert rules and receive notifications disclosing target system names and metrics.
References7
- github.com/henrygd/beszel
- github.com/henrygd/beszel/blob/v0.18.8/internal/alerts/alerts_a…
- github.com/henrygd/beszel/commit/6f92b9396dfbacaf71c20444d175af…
- github.com/henrygd/beszel/releases/tag/v0.19.0
- github.com/henrygd/beszel/security/advisories/GHSA-759g-ch5m-2g…
- www.vulncheck.com/advisories/beszel-before-0.19.0-insecure-dire…
- github.com/henrygd/beszel/security/advisories/GHSA-759g-ch5m-2g…
Metrics
- CVSS 3.1
-
4.2
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N - CVSS 4.0
-
2.3
LOW
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 23 · as of 8 November 2026
- CWE
- CWE-639
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.