SCALANCE LPE9403: Authentication Bypass Using an Alternate Path or Channel
CVE-2025-40581 is a high-severity authentication bypass using an alternate path or channel vulnerability in SCALANCE LPE9403 from Siemens, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version V2.1 HF0 as the first without the flaw, so updating SCALANCE LPE9403 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update SCALANCE LPE9403 to V2.1 HF0 or a later version.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | SCALANCE LPE9403 | before V2.1 HF0 | V2.1 HF0 |
| Siemens | Scalance Lpe9403 Firmware | Not specified in the record | Not stated |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.4 | High | CNA (siemens.com) |
| CVSS 3.1 | 7.1 | High | CNA (siemens.com) |
Official description
A vulnerability has been identified in SCALANCE LPE9403 (6GK5998-3GS00-2AC2) (All versions < V2.1 HF0 with SINEMA Remote Connect Edge Client installed). Affected devices are vulnerable to an authentication bypass. This could allow a non-privileged local attacker to bypass the authentication of the SINEMA Remote Connect Edge Client, and to read and modify the configuration parameters.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass Using an Alternate Path or Channel
The product requires authentication, but the product has an alternate path or channel that does not require authentication.
How developers prevent this class of flaw
- Funnel all access through a single choke point to simplify how users can access a resource. For every access, perform a check to determine if the user has permissions to access the resource.
More Authentication Bypass Using an Alternate Path or Channel vulnerabilities (CWE-288)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in SCALANCE LPE9403
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 7.2 High severity
Recent Authentication Bypass Using an Alternate Path or Channel vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.1 Critical severity
- 9.8 Critical severity
- 7.3 High severity
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