CyberSecBulletin
CVE-2025-3091NVD status: Deferred

mbCONNECT24: Authorization Bypass Through User-Controlled Key

Published Updated By the CyberSecBulletin desk

CVE-2025-3091 is a high-severity authorization bypass through user-controlled key vulnerability in mbCONNECT24 from MB connect line, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 2.16.5 as the first without the flaw, so updating mbCONNECT24 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.38% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update mbCONNECT24 to 2.16.5 or a later version.
  2. Update mymbCONNECT24 to 2.18.0 or 2.16.5, whichever matches your release line, or a later version.
  3. Update myREX24 to 2.18.0 or 2.16.5, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
MB connect linembCONNECT24before 2.16.52.16.5
MB connect linemymbCONNECT24before 2.18.0; before 2.16.52.18.0, 2.16.5
HelmholzmyREX24before 2.18.0; before 2.16.52.18.0, 2.16.5
HelmholzmyREX24.virtualbefore 2.18.0; before 2.16.52.18.0, 2.16.5

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cert.vde.com).

Official description

An low privileged remote attacker in possession of the second factor for another user can login as that user without knowledge of the other user`s password.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

How developers prevent this class of flaw

  • For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
  • Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
  • Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.

More Authorization Bypass Through User-Controlled Key vulnerabilities (CWE-639)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in mbCONNECT24

All mbCONNECT24 vulnerabilities

Recent Authorization Bypass Through User-Controlled Key vulnerabilities

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