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 Updat…

published 2025-05-13 17 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-14680

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

Siemens SIMATIC PCS neo V4.1 V4.1 Update 3
Siemens SIMATIC PCS neo V5.0 V5.0 Update 1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-25-135-12 updated 2025-05-13 cvss 8.8

Siemens SIMATIC PCS

Siemens SIMATIC PCS neo V4.1 <V4.1_Update_3
affected: fixed in V4.1 support.industry.siemens.com
Siemens SIMATIC PCS neo V5.0 <V5.0_Update_1
affected: fixed in V5.0 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 17 mo ago (2025-05-13)

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Siemens SIMATIC PCS neo V4.1
Siemens SIMATIC PCS neo V5.0

Classification

Weakness

CWE-613 DEPRECATED: Insufficient Session Expiration

References

cert-portal.siemens.com /productcert/html/ssa-339086.html
vendor-advisory

Sources

CVE List CVE-2025-40566
NVD CVE-2025-40566

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary