A Predictable Value Range from Previous Values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts limited integrity, and limited availability for affected systems. Impacting 6 products from schneider-electric, from schneider-electric, from schneider-electric and 3 others, organizations running these solutions should prioritize assessment and patching.
First disclosed in 2017, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.
2017-06-30T03:29:00.390
2025-04-20T01:37:25.860
Deferred
CVSSv3.1: 6.5 (MEDIUM)
AV:N/AC:L/Au:N/C:N/I:P/A:P
10.0
4.9
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | schneider-electric | modicon_m241_firmware | ≤ 4.0.3.20 | Yes |
| Hardware | schneider-electric | modicon_m241 | - | No |
| Operating System | schneider-electric | modicon_m251_firmware | ≤ 4.0.3.20 | Yes |
| Hardware | schneider-electric | modicon_m251 | - | No |
| Operating System | schneider-electric | modicon_m221_firmware | ≤ 1.1.1.5 | Yes |
| Hardware | schneider-electric | modicon_m221 | - | No |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For schneider-electric's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.