SCALANCE LPE9403: Improper Check for Dropped Privileges
CVE-2025-27396 is a high-severity improper check for dropped privileges vulnerability in SCALANCE LPE9403 from Siemens, with a CVSS 3.1 base score of 8.8 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 V4.0 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 0.44% 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 V4.0 or a later version.
- Update Scalance Lpe9403 Firmware to 4.0 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 V4.0 | V4.0 |
| Siemens | Scalance Lpe9403 Firmware | before 4.0 | 4.0 |
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
- 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
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (siemens.com) |
| CVSS 3.1 | 8.8 | High | CNA (siemens.com) |
Official description
A vulnerability has been identified in SCALANCE LPE9403 (6GK5998-3GS00-2AC2) (All versions < V4.0). Affected devices do not properly limit the elevation of privileges required to perform certain valid functionality. This could allow an authenticated lowly-privileged remote attacker to escalate their privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Check for Dropped Privileges
The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded.
How developers prevent this class of flaw
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
- Check the results of all functions that return a value and verify that the value is expected.
- In Windows, make sure that the process token has the SeImpersonatePrivilege(Microsoft Server 2003). Code that relies on impersonation for security must ensure that the impersonation succeeded, i.e., that a proper privilege demotion happened.
More Improper Check for Dropped Privileges vulnerabilities (CWE-273)
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
- 7.1 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.2 High severity
Recent Improper Check for Dropped Privileges vulnerabilities
- 8.5 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.2 High severity
- 7.8 High severity
- 7.8 High severity
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