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Fencer Intel
medium 6.5

CVE-2017-6030 json

Schneider Electric Modicon PLCs Predictable Value Range from Previous Values

published 2017-06-30 9 y ago modified 2026-06-17 4 mo ago also EUVD-2017-15098

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

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.

Patch / fix

  • Schneider Electric Modicon M221 1.5.0.0
  • Schneider Electric Modicon M241 4.0.5.11
  • Schneider Electric Modicon M251 4.0.5.11

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 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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

2.18% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:N/I:P/A:P

Affected products

  • Schneider Electric Modicon M221
  • Schneider Electric Modicon M241
  • Schneider Electric Modicon M251

Classification

Weakness
  • CWE-343 Predictable Value Range from Previous Values
  • CWE-331 Insufficient Entropy

References

Sources

Fencer Intel 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.