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CVE-2025-40759VulnerabilityPublished Updated

CVE-2025-40759: Siemens SIMATIC S7-PLCSIM V17 · Deserialization of Untrusted Data

Affects Siemens SIMATIC S7-PLCSIM V17Source CVE Database V5

0

Not known to be exploited · CVSS 7.8 High : upgrade to 5.2.1.1 soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.2.1.1, 5.2.2.2
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade TIA Portal Cloud to 5.2.1.1 (V19) or 5.2.2.2 (V20).

Affected software

ProductAffectedFixed in
SiemensSIMATIC S7-PLCSIM V17Affected
  • All versions
Fixed in–
SiemensSIMATIC STEP 7 V17Affected
  • =0
Fixed in–
SiemensSIMATIC STEP 7 V18Affected
  • =0
Fixed in–
SiemensSIMATIC STEP 7 V19Affected
  • =0
Fixed in–
SiemensSIMATIC STEP 7 V20Affected
  • =0
Fixed in–
SiemensSIMATIC WinCC V17Affected
  • =0
Fixed in–
SiemensSIMATIC WinCC V18Affected
  • =0
Fixed in–
SiemensSIMATIC WinCC V19Affected
  • =0
Fixed in–
SiemensSIMATIC WinCC V20Affected
  • =0
Fixed in–
SiemensSIMOCODE ES V17Affected
  • All versions
Fixed in–
SiemensSIMOCODE ES V18Affected
  • All versions
Fixed in–
SiemensSIMOCODE ES V19Affected
  • All versions
Fixed in–
SiemensSIMOCODE ES V20Affected
  • All versions
Fixed in–
SiemensSIMOTION SCOUT TIA V5.4Affected
  • All versions
Fixed in–
SiemensSIMOTION SCOUT TIA V5.5Affected
  • All versions
Fixed in–
SiemensSIMOTION SCOUT TIA V5.6Affected
  • =0
Fixed in–
SiemensSIMOTION SCOUT TIA V5.7Affected
  • All versions
Fixed in–
SiemensSINAMICS Startdrive V17Affected
  • All versions
Fixed in–
SiemensSINAMICS Startdrive V18Affected
  • All versions
Fixed in–
SiemensSINAMICS Startdrive V19Affected
  • All versions
Fixed in–
SiemensSINAMICS Startdrive V20Affected
  • All versions
Fixed in–
SiemensSIRIUS Safety ES V17 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Safety ES V18 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Safety ES V19 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Safety ES V20 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Soft Starter ES V17 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Soft Starter ES V18 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Soft Starter ES V19 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensSIRIUS Soft Starter ES V20 (TIA Portal)Affected
  • All versions
Fixed in–
SiemensTIA Portal Cloud V17Affected
  • All versions
Fixed in–
SiemensTIA Portal Cloud V18Affected
  • All versions
Fixed in–
SiemensTIA Portal Cloud V19Affected
  • <5.2.1.1
Fixed in
  • 5.2.1.1
SiemensTIA Portal Cloud V20Affected
  • <5.2.2.2
Fixed in
  • 5.2.2.2

AI-suggested

Organizations should immediately implement strict controls on the handling and transfer of project files, ensuring only trusted and verified files are opened within affected Siemens software. Engineering workstations should be isolated from untrusted networks and have limited user privileges to reduce the risk of exploitation. Siemens updates and patches should be applied promptly once available, and vendors should be monitored for security advisories. Network segmentation between IT and OT environments should be enforced to limit lateral movement. Employ application whitelisting and endpoint detection and response (EDR) solutions on engineering systems to detect anomalous behavior indicative of exploitation. Regular backups of project files and system configurations should be maintained to enable recovery. Additionally, user training on the risks of opening untrusted files can reduce the likelihood of successful social engineering attacks. Finally, consider deploying virtualized or sandboxed environments for testing and importing project files to contain potential malicious activity.

Description

A vulnerability has been identified in SIMATIC S7-PLCSIM V17 (All versions), SIMATIC STEP 7 V17 (All versions < V17 Update 9), SIMATIC STEP 7 V18 (All versions < V18 Update 6), SIMATIC STEP 7 V19 (All versions < V19 Update 4), SIMATIC STEP 7 V20 (All versions < V20 Update 4), SIMATIC WinCC V17 (All versions < V17 Update 9), SIMATIC WinCC V18 (All versions < V18 Update 6), SIMATIC WinCC V19 (All versions < V19 Update 4), SIMATIC WinCC V20 (All versions < V20 Update 4), SIMOCODE ES V17 (All versions), SIMOCODE ES V18 (All versions), SIMOCODE ES V19 (All versions), SIMOCODE ES V20 (All versions), SIMOTION SCOUT TIA V5.4 (All versions), SIMOTION SCOUT TIA V5.5 (All versions), SIMOTION SCOUT TIA V5.6 (All versions < V5.6 SP1 HF7), SIMOTION SCOUT TIA V5.7 (All versions), SINAMICS Startdrive V17 (All versions), SINAMICS Startdrive V18 (All versions), SINAMICS Startdrive V19 (All versions), SINAMICS Startdrive V20 (All versions), SIRIUS Safety ES V17 (TIA Portal) (All versions), SIRIUS Safety ES V18 (TIA Portal) (All versions), SIRIUS Safety ES V19 (TIA Portal) (All versions), SIRIUS Safety ES V20 (TIA Portal) (All versions), SIRIUS Soft Starter ES V17 (TIA Portal) (All versions), SIRIUS Soft Starter ES V18 (TIA Portal) (All versions), SIRIUS Soft Starter ES V19 (TIA Portal) (All versions), SIRIUS Soft Starter ES V20 (TIA Portal) (All versions), TIA Portal Cloud V17 (All versions), TIA Portal Cloud V18 (All versions), TIA Portal Cloud V19 (All versions < V5.2.1.1), TIA Portal Cloud V20 (All versions < V5.2.2.2). Affected products do not properly sanitize stored security properties when parsing project files. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application.

References

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