🛡️ CVE-2025-40820

🟠 CVSS 7.5 — High ✅ No Known Exploit CWE-940 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Affected software

CVE-2025-40820 is recorded against 1 package.

  • unknown

Timeline and source

Published on 9 December 2025 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

cert-portal.siemens.com

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-940
Public Exploit ✅ No
Source NVD
Published 2025-12-09
Updated 2026-08-11
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
unknown — —

Similar Threats

Site Security Check

Is the affected software part of your stack?

CVE-2025-40820 is rated CVSS 7.5 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.