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Fencer Intel
low 3.5

CVE-2026-40077 json

Beszel has an IDOR in hub API endpoints that read system ID from URL parameter

published 7mo ago modified 14d ago also EUVD-2026-21047 , GHSA-5f5r-95pg-xrpm , GO-2026-5141

cvss
3.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 13%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/henrygd/beszel 0.18.7
  • beszel beszel 0.18.7
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Is CVE-2026-40077 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/henrygd/beszel/security/advisories/GHSA-5f5r-95pg-xrpm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
GitHub 3.1 3.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
NVD 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
go github.com/henrygd/beszel
<0.18.7
0.18.7

Affected products

  • henrygd beszel

Classification

Weakness
  • CWE-184 Incomplete List of Disallowed Inputs

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.