CVE-2025-40820
Affected products do not properly enforce TCP sequence number validation in specific scenarios but accept values within a broad range. This could allow an unauthenticated remote attacker e.g. to interfere with connection setup, potentially leading to a denial of service. The attack succeeds only if an attacker can inject IP packets with spoofed addresses at precisely timed moments, and it affects only TCP-based services.
Published:Dec 9, 2025
Last Modified:Apr 15, 2026
EPS:Dec 9, 2025
EPSS Score:0.00133
CVSS Score:7.5
Affected Products
Vendor
Product
Action
Vendor
Siemens
Product
Sidoor Atd430w
Siemens
Sidoor Atd430w
Vendor
Siemens
Product
Sidoor Ate530s Coated
Siemens
Sidoor Ate530s Coated
Vendor
Siemens
Product
Simatic
Siemens
Simatic
Vendor
Siemens
Product
Simatic Cfc
Siemens
Simatic Cfc
Vendor
Siemens
Product
Simatic Cfu Diq
Siemens
Simatic Cfu Diq
Vendor
Siemens
Product
Simatic Cfu Pa
Siemens
Simatic Cfu Pa
Vendor
Siemens
Product
Simatic Et200al Im 157-1 Pn
Siemens
Simatic Et200al Im 157-1 Pn
Vendor
Siemens
Product
Simatic Et200sp Im155-6 Mf Hf
Siemens
Simatic Et200sp Im155-6 Mf Hf
Vendor
Siemens
Product
Simatic Et 200mp Im 155-5 Pn Hf
Siemens
Simatic Et 200mp Im 155-5 Pn Hf
Vendor
Siemens
Product
Simatic Et 200s
Siemens
Simatic Et 200s
Vendor
Siemens
Product
Simatic Pcs
Siemens
Simatic Pcs
Vendor
Siemens
Product
Simatic Pdm
Siemens
Simatic Pdm
Vendor
Siemens
Product
Simatic S7-1500 Cpu 1510sp-1 Pn
Siemens
Simatic S7-1500 Cpu 1510sp-1 Pn
Vendor
Siemens
Product
Simatic S7-1500 Cpu 1510sp F-1 Pn
Siemens
Simatic S7-1500 Cpu 1510sp F-1 Pn
Vendor
Siemens
Product
Simatic S7-1500 Cpu 1512sp-1 Pn
Siemens
Simatic S7-1500 Cpu 1512sp-1 Pn
Vendor
Siemens
Product
Simatic S7-1500 Cpu 1512sp F-1 Pn
Siemens
Simatic S7-1500 Cpu 1512sp F-1 Pn
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
