CVE-2026-35227 Improper resource management in CODESYS Modbus TCP Server
An unauthenticated remote attacker can exhaust TCP connections via a race condition, causing denial of service for legitimate clients.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-35227?
CVE-2026-35227 is a high-severity vulnerability in CODESYS Modbus, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An unauthenticated remote attacker may exhaust all available TCP connections in the CODESYS Modbus TCP Server stack if a race condition in connection handling is successfully exploited, preventing legitimate clients from establishing new connections.
Weakness: CWE-772
Which versions are affected by CVE-2026-35227?
How do I fix CVE-2026-35227?
No fix has been published for CVE-2026-35227 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-35227 being exploited?
There is no known exploitation of CVE-2026-35227 in the wild and no public exploit code.
Sources
Also known as GHSA-qc33-pwh4-j9rq.