CVE-2026-3869 Auth bypass in Modicon M580
Incorrect authentication implementation allows attackers to compromise confidentiality, integrity, and availability of Modicon PLCs when running lower-level applications.
- 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-2026-3869?
CVE-2026-3869 is a critical authentication bypass vulnerability in Schneider Electric Modicon M580, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
CWE-303 : Incorrect Implementation of Authentication Algorithm vulnerability exists that could cause loss of confidentiality, integrity and availability of the PLC provided an application project with a lower application level is running on the PLC.
Weakness: CWE-303
Which versions are affected by CVE-2026-3869?
How do I fix CVE-2026-3869?
No fix has been published for CVE-2026-3869 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-3869 being exploited?
There is no known exploitation of CVE-2026-3869 in the wild and no public exploit code.
Sources
Also known as GHSA-g6jw-g6wr-2qcc.