CVE-2017-6026

mediumpriority · attend · 57OT risk · highEPSS 0.318 · 98 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

31.8% (98th) EPSS

CVSS 6.4 · medium

Is it mine?

13 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · cisa_csaf_ot · nvd

EPSS · scored 2026-10-23

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.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

No vendor fix yet; a mitigation is available.

MitigationModicon M221cisa_csaf_ot
Do not grant [network] access to unknown computers
MitigationModicon M241cisa_csaf_ot
Do not grant [network] access to unknown computers
MitigationModicon M251cisa_csaf_ot
Do not grant [network] access to unknown computers

cvss

Technical severity, 0–10. One row per scoring source.

9.1

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.4–9.1

v2.06.4mediumAV:N/AC:L/Au:N/C:P/I:P/A:Nprimary · NVD / NIST USexploitability 10 · impact 4.9

v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 5.2

v3.06.5mediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · CISA US

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:Psecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-330USprimaryCWE-330US

exploits (1)

Public proof-of-concept and weaponised exploit code.

EDB-45918Schneider Electric PLC - Session Calculation Authentication BypassPoC · exploit_db

affected products (13)

Products and version ranges known to be affected.

Modicon M221: firmware versions prior to Version 1.5.0.0all versionscisa_csaf_otUS
Modicon M241: all versionsall versionscisa_csaf_otUS
Modicon M241: firmware versions prior to Version 4.0.5.11all versionscisa_csaf_otUS
Modicon M251: all versionsall versionscisa_csaf_otUS
Modicon M251: firmware versions prior to Version 4.0.5.11all versionscisa_csaf_otUS
Schneider Electric Software, LLC Modicon M221< 1.5.0.0cisa_csaf_otUS
Schneider Electric Software, LLC Modicon M241all versionscisa_csaf_otUS
Schneider Electric Software, LLC Modicon M241< 4.0.5.11cisa_csaf_otUS
Schneider Electric Software, LLC Modicon M251all versionscisa_csaf_otUS
Schneider Electric Software, LLC Modicon M251< 4.0.5.11cisa_csaf_otUS
n/a Schneider Electric Modicon PLCs≤ Schneider Electric Modicon PLCsenisa_euvdEU
schneider-electric modicon m241 firmware≤ 4.0.3.20nvdUScpe:2.3:o:schneider-electric:modicon_m241_firmware:*:*:*:*:*:*:*:*
schneider-electric modicon m251 firmware≤ 4.0.3.20nvdUScpe:2.3:o:schneider-electric:modicon_m251_firmware:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

ICSA-17-089-02Schneider Electric Modicon PLCs2017-03-30icsa · cisa_csaf_otUS
ATTENTION: Remotely exploitable/low skill level to exploit.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cisa_csaf_ot nvd NVD CVE.org MITRE

published 2017-06-30modified 2026-06-17

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references (10)

External citations — patches, advisories, analysis.

scry

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