Back to Database
Status published
High
CVE-2025-40820
Affected products do not properly enforce TCP sequence number validation...
Vulnerability Description
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.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
THREAT MONITOR
Am I Vulnerable?
Launch our assessment wizard to check if your infrastructure is exposed to • CVE-2025-40820
Credits & Attribution
No credits recorded in the NVD database.
More from Siemens
View All →CVE-2025-41224
A vulnerability has been identified in RUGGEDCOM RMC8388 V5.X (All...
High
7.7
CVE-2025-41223
A vulnerability has been identified in RUGGEDCOM i800 (All versions),...
Medium
6.3
CVE-2025-41222
A vulnerability has been identified in RUGGEDCOM i800 (All versions),...
Medium
6.9
CVE-2025-40949
A vulnerability has been identified in RUGGEDCOM ROX MX5000 (All...
High
8.9
CVE-2025-40948
A vulnerability has been identified in RUGGEDCOM ROX MX5000 (All...
Medium
6.1
Affected Vendor
Siemens
View all reports →Affected Software
SIDOOR ATD430W, SIDOOR ATE530G COATED, SIDOOR ATE530S COATED, SIMATIC CFU DIQ, SIMATIC CFU PA, SIMATIC ET 200AL IM 157-1 PN, SIMATIC ET 200clean, CM 8x IO-Link, SIMATIC ET 200clean, DI 16x24VDC, SIMATIC ET 200clean, DIQ 16x24VDC/0,5A, SIMATIC ET 200eco PN, AI 8xRTD/TC, M12-L, SIMATIC ET 200eco PN, CM 4x IO-Link, M12-L, SIMATIC ET 200eco PN, CM 8x IO-Link, M12-L, SIMATIC ET 200eco PN, DI 16x24VDC, M12-L, SIMATIC ET 200eco PN, DI 8x24VDC, M12-L, SIMATIC ET 200eco PN, DIQ 16x24VDC/2A, M12-L, SIMATIC ET 200eco PN, DQ 8x24VDC/0,5A, M12-L, SIMATIC ET 200eco PN, DQ 8x24VDC/2A, M12-L, SIMATIC ET 200MP IM 155-5 PN HF, SIMATIC ET 200pro IM 154-8 PN/DP CPU, SIMATIC ET 200pro IM 154-8F PN/DP CPU, SIMATIC ET 200pro IM 154-8FX PN/DP CPU, SIMATIC ET 200S IM 151-8 PN/DP CPU, SIMATIC ET 200S IM 151-8F PN/DP CPU, SIMATIC ET 200SP CPU 1510SP F-1 PN, SIMATIC ET 200SP CPU 1510SP-1 PN, SIMATIC ET 200SP CPU 1512SP F-1 PN, SIMATIC ET 200SP CPU 1512SP-1 PN, SIMATIC ET 200SP IM 155-6 MF HF, SIMATIC ET 200SP IM 155-6 PN HA (incl. SIPLUS variants), SIMATIC ET 200SP IM 155-6 PN HF, SIMATIC ET 200SP IM 155-6 PN/2 HF, SIMATIC ET 200SP IM 155-6 PN/3 HF, SIMATIC PN/MF Coupler, SIMATIC PN/PN Coupler, SIMATIC Power Line Booster PLB, Base Module, SIMATIC Power Line Booster PLB, Modem Module ST, SIMATIC S7-1200 CPU 1211C AC/DC/Rly, SIMATIC S7-1200 CPU 1211C DC/DC/DC, SIMATIC S7-1200 CPU 1211C DC/DC/Rly, SIMATIC S7-1200 CPU 1212C AC/DC/Rly, SIMATIC S7-1200 CPU 1212C DC/DC/DC, SIMATIC S7-1200 CPU 1212C DC/DC/Rly, SIMATIC S7-1200 CPU 1212FC DC/DC/DC, SIMATIC S7-1200 CPU 1212FC DC/DC/Rly, SIMATIC S7-1200 CPU 1214C AC/DC/Rly, SIMATIC S7-1200 CPU 1214C DC/DC/DC, SIMATIC S7-1200 CPU 1214C DC/DC/Rly, SIMATIC S7-1200 CPU 1214FC DC/DC/DC, SIMATIC S7-1200 CPU 1214FC DC/DC/Rly, SIMATIC S7-1200 CPU 1215C AC/DC/Rly, SIMATIC S7-1200 CPU 1215C DC/DC/DC, SIMATIC S7-1200 CPU 1215C DC/DC/Rly, SIMATIC S7-1200 CPU 1215FC DC/DC/DC, SIMATIC S7-1200 CPU 1215FC DC/DC/Rly, SIMATIC S7-1200 CPU 1217C DC/DC/DC, SIMATIC S7-1500 CPU 1511-1 PN, SIMATIC S7-1500 CPU 1511F-1 PN, SIMATIC S7-1500 CPU 1513-1 PN, SIMATIC S7-1500 CPU 1513F-1 PN, SIMATIC S7-1500 CPU 1515-2 PN, SIMATIC S7-1500 CPU 1515F-2 PN, SIMATIC S7-1500 CPU 1516-3 PN/DP, SIMATIC S7-1500 CPU 1516F-3 PN/DP, SIMATIC S7-200 SMART CPU CR40, SIMATIC S7-200 SMART CPU CR60, SIMATIC S7-200 SMART CPU SR20, SIMATIC S7-200 SMART CPU SR30, SIMATIC S7-200 SMART CPU SR40, SIMATIC S7-200 SMART CPU SR60, SIMATIC S7-200 SMART CPU ST20, SIMATIC S7-200 SMART CPU ST30, SIMATIC S7-200 SMART CPU ST40, SIMATIC S7-200 SMART CPU ST60, SIMATIC S7-300 CPU 314C-2 PN/DP, SIMATIC S7-300 CPU 315-2 PN/DP, SIMATIC S7-300 CPU 315F-2 PN/DP, SIMATIC S7-300 CPU 315T-3 PN/DP, SIMATIC S7-300 CPU 317-2 PN/DP, SIMATIC S7-300 CPU 317F-2 PN/DP, SIMATIC S7-300 CPU 317T-3 PN/DP, SIMATIC S7-300 CPU 317TF-3 PN/DP, SIMATIC S7-300 CPU 319-3 PN/DP, SIMATIC S7-300 CPU 319F-3 PN/DP, SIMATIC S7-400 CPU 412-2 PN V7, SIMATIC S7-400 CPU 414-3 PN/DP V7, SIMATIC S7-400 CPU 414F-3 PN/DP V7, SIMATIC S7-400 CPU 416-3 PN/DP V7, SIMATIC S7-400 CPU 416F-3 PN/DP V7, SIMATIC S7-400 H V6 CPU family (incl. SIPLUS variants), SIMATIC S7-410 V10 CPU family (incl. SIPLUS variants), SIMATIC S7-410 V8 CPU family (incl. SIPLUS variants), SIMATIC TDC CP51M1, SIMATIC TDC CPU555, SIMOCODE pro V Ethernet/IP (incl. SIPLUS variants), SIMOCODE pro V PROFINET, SINUMERIK 840D sl, SIPLUS ET 200MP IM 155-5 PN HF, SIPLUS ET 200MP IM 155-5 PN HF T1 RAIL, SIPLUS ET 200S IM 151-8 PN/DP CPU, SIPLUS ET 200S IM 151-8F PN/DP CPU, SIPLUS ET 200SP CPU 1512SP F-1 PN, SIPLUS ET 200SP IM 155-6 PN HF, SIPLUS ET 200SP IM 155-6 PN HF T1 RAIL, SIPLUS ET 200SP IM 155-6 PN HF TX RAIL, SIPLUS HCS4200 CIM4210, SIPLUS HCS4200 CIM4210C, SIPLUS HCS4300 CIM4310, SIPLUS NET PN/PN Coupler, SIPLUS S7-1200 CPU 1212 AC/DC/RLY, SIPLUS S7-1200 CPU 1212 DC/DC/RLY, SIPLUS S7-1200 CPU 1212C AC/DC/RLY, SIPLUS S7-1200 CPU 1212C DC/DC/DC, SIPLUS S7-1200 CPU 1212C DC/DC/DC RAIL, SIPLUS S7-1200 CPU 1214 AC/DC/RLY, SIPLUS S7-1200 CPU 1214 DC/DC/RLY, SIPLUS S7-1200 CPU 1214C AC/DC/RLY, SIPLUS S7-1200 CPU 1214C DC/DC/DC, SIPLUS S7-1200 CPU 1214C DC/DC/DC RAIL, SIPLUS S7-1200 CPU 1214C DC/DC/RLY, SIPLUS S7-1200 CPU 1214FC DC/DC/DC, SIPLUS S7-1200 CPU 1214FC DC/DC/RLY, SIPLUS S7-1200 CPU 1215 AC/DC/RLY, SIPLUS S7-1200 CPU 1215 DC/DC/DC, SIPLUS S7-1200 CPU 1215 DC/DC/RLY, SIPLUS S7-1200 CPU 1215C AC/DC/RLY, SIPLUS S7-1200 CPU 1215C DC/DC/DC, SIPLUS S7-1200 CPU 1215FC DC/DC/DC, SIPLUS S7-1500 CPU 1511-1 PN, SIPLUS S7-1500 CPU 1511F-1 PN, SIPLUS S7-1500 CPU 1513-1 PN, SIPLUS S7-1500 CPU 1513F-1 PN, SIPLUS S7-1500 CPU 1516-3 PN/DP, SIPLUS S7-1500 CPU 1516F-3 PN/DP, SIPLUS S7-300 CPU 314C-2 PN/DP, SIPLUS S7-300 CPU 315-2 PN/DP, SIPLUS S7-300 CPU 315F-2 PN/DP, SIPLUS S7-300 CPU 317-2 PN/DP, SIPLUS S7-300 CPU 317F-2 PN/DP, SIPLUS S7-400 CPU 414-3 PN/DP V7, SIPLUS S7-400 CPU 416-3 PN/DP V7, SIWAREX WP231, SIWAREX WP241, SIWAREX WP251, SIWAREX WP521 ST, SIWAREX WP522 ST
Vulnerable Versions:
0, V5.1.1, V4.2.0
Timeline
Official Publish:
December 9th, 2025
Last Modified:
December 9th, 2025
Added to House:
July 22nd, 2026
CVSS Vectors
V3:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses (CWE)
MITRE ATT&CK TTPs
No associated TTPs found for this vulnerability.