A vulnerability has been identified in SIMATIC PCS neo V4.1 (All versions < V4.1 Update 3)…
CVE-2025-40566 is a critical-severity vulnerability in SIMATIC PCS neo V4.1 from Siemens, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version V4.1 Update 3 as the first without the flaw, so updating SIMATIC PCS neo V4.1 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update SIMATIC PCS neo V4.1 to V4.1 Update 3 or a later version.
- Update SIMATIC PCS neo V5.0 to V5.0 Update 1 or a later version.
- Update Simatic Pcs Neo to 4.1 or 5.0, whichever matches your release line, or a later version.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | SIMATIC PCS neo V4.1 | before V4.1 Update 3 | V4.1 Update 3 |
| Siemens | SIMATIC PCS neo V5.0 | before V5.0 Update 1 | V5.0 Update 1 |
| Siemens | Simatic Pcs Neo | before 4.1; before 5.0; 4.1; 5.0 | 4.1, 5.0 |
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
- NoneNo account or login is needed.
- 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:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (siemens.com) |
| CVSS 3.1 | 8.8 | High | CNA (siemens.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
A vulnerability has been identified in SIMATIC PCS neo V4.1 (All versions < V4.1 Update 3), SIMATIC PCS neo V5.0 (All versions < V5.0 Update 1). Affected products do not correctly invalidate user sessions upon user logout. This could allow a remote unauthenticated attacker, who has obtained the session token by other means, to re-use a legitimate user's session even after logout.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
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 SIMATIC PCS neo V4.1
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 8.2 High severity
- 7.5 High severity
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