Schneider PLC Auth Algorithm Flaw
CVE-2026-3869 Published on September 11, 2026
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.
Vulnerability Analysis
CVE-2026-3869 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
Incorrect Implementation of Authentication Algorithm
The requirements for the software dictate the use of an established authentication algorithm, but the implementation of the algorithm is incorrect. This incorrect implementation may allow authentication to be bypassed.
Affected Versions
Schneider Electric Modicon M580:- Version All versions with an application level below 4.00 is affected.
- Version All versions with an application level below 4.20 is affected.