CVE-2025-40820Affected products do not properly enforce TCP sequence number validation in specific scenarios but accept values within a broad range.
Updated under an hour ago ()
Does this affect you?
It lists no affected products yet. Add what you run and Signals checks it as products are added.
No exploitation reported and no EPSS estimate yet.
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
- 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-940
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Deferred
- Record last updated
- Oct 7, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
No affected products are listed yet.
References
- https://cert-portal.siemens.com/productcert/html/ssa-915282.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.