A Use of Insufficiently Random Values issue was discovered in Schneider Electric Modicon PLCs Modicon M241, firmware versions prior to Vers…

published 2017-06-30 9 y ago modified 2026-06-17 4 mo ago also EUVD-2017-15094

cvss: 9.1; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 31.8%; EPSS 31.8% chance of exploitation in 30 days, percentile 98%
public exploits: 1; Exploit-DB

A Use of Insufficiently Random Values issue was discovered in Schneider Electric Modicon PLCs Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The session numbers generated by the web application are lacking randomization and are shared between several users. This may allow a current session to be compromised.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-17-089-02 updated 2017-03-30 cvss 6.5

Schneider Electric Modicon PLCs

Schneider Electric Software, LLC Modicon M221 < 1.5.0.0 Schneider Electric Software, LLC Modicon M241 < 4.0.5.11 Schneider Electric Software, LLC Modicon M251 < 4.0.5.11
affected: mitigation “SoMachineBasic, Version 1.5, is available”

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Timeline

2017-06-30 Published
2018-11-30 First public exploit (EDB-45918)

Exploit prediction

31.82% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

EDB-45918 Schneider Electric PLC - Session Calculation Authentication Bypass webapps, 2018-11-30

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD	2.0	6.4	AV:N/AC:L/Au:N/C:P/I:P/A:N

Affected products

n/a Schneider Electric Modicon PLCs

Classification

Weakness

CWE-330 Use of Insufficiently Random Values

References

exploit-db.com /exploits/45918/
exploit, third-party-advisory, vdb-entry
ics-cert.us-cert.gov /advisories/ICSA-17-089-02
third-party-advisory, us-government-resource
securityfocus.com /bid/97254
vdb-entry, third-party-advisory

Sources

CVE List CVE-2017-6026
NVD CVE-2017-6026

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary