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Vulnerability · Published Dec 9, 2025 · Assigned by siemens

CVE-2025-40820

High 7.5

In plain English

A high-severity security flaw in SIDOOR ATD430W from Siemens. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 57.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
Siemens SIDOOR ATD430W 0 – before *
Siemens SIDOOR ATE530G COATED 0 – before *
Siemens SIDOOR ATE530S COATED 0 – before *
Siemens SIMATIC CFU DIQ 0 – before V2.0.0
Siemens SIMATIC CFU PA 0 – before V2.0.0
Siemens SIMATIC CFU PA 0 – before V2.0.0
Siemens SIMATIC ET 200AL IM 157-1 PN 0 – before *
Siemens SIMATIC ET 200clean, CM 8x IO-Link 0 – before *
Siemens SIMATIC ET 200clean, DI 16x24VDC 0 – before *
Siemens SIMATIC ET 200clean, DIQ 16x24VDC/0,5A 0 – before *
Siemens SIMATIC ET 200eco PN, AI 8xRTD/TC, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, CM 4x IO-Link, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, CM 8x IO-Link, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, CM 8x IO-Link, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, DI 16x24VDC, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, DI 8x24VDC, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, DIQ 16x24VDC/2A, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, DQ 8x24VDC/0,5A, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200eco PN, DQ 8x24VDC/2A, M12-L V5.1.1 – before *
Siemens SIMATIC ET 200MP IM 155-5 PN HF V4.2.0 – before *
Siemens SIMATIC ET 200pro IM 154-8 PN/DP CPU 0 – before *
Siemens SIMATIC ET 200pro IM 154-8F PN/DP CPU 0 – before *
Siemens SIMATIC ET 200pro IM 154-8FX PN/DP CPU 0 – before *
Siemens SIMATIC ET 200S IM 151-8 PN/DP CPU 0 – before *
Siemens SIMATIC ET 200S IM 151-8F PN/DP CPU 0 – before *
Siemens SIMATIC ET 200SP CPU 1510SP F-1 PN 0 – before *
Siemens SIMATIC ET 200SP CPU 1510SP-1 PN 0 – before *
Siemens SIMATIC ET 200SP CPU 1512SP F-1 PN 0 – before *
Siemens SIMATIC ET 200SP CPU 1512SP-1 PN 0 – before *
Siemens SIMATIC ET 200SP IM 155-6 MF HF 0 – before *

Weakness: CWE-940 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References