CVE-2025-40820 — HIGH (7.5)

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.

CVSS Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Related Weaknesses (CWE)

CWE-940

References

https://cert-portal.siemens.com/productcert/html/ssa-915282.html

FAQ

What is CVE-2025-40820?

CVE-2025-40820 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 inter...

How severe is CVE-2025-40820?

CVE-2025-40820 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-40820?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.