CVE-2018-7791

highpriority · track · 40EPSS 0.019 · 80 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.90% (80th) EPSS

CVSS 7.5 · high

Is it mine?

5 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · cisa_csaf_ot

EPSS · scored 2026-10-27

A Permissions, Privileges, and Access Control vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior to firmware V1.6.2.0). The vulnerability allows unauthorized users to overwrite the original password with their password. If an attacker exploits this vulnerability and overwrite the password, the attacker can upload the original program from the PLC.

remediations

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

No vendor fix yet; a mitigation is available.

MitigationModicon M221 all referencescisa_csaf_ot
As a temporary mitigation, Modicon M221 users should take the following measures: Set up a firewall blocking all remote/external access to Port 502.

cvss

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

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.07.7highCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Lsecondary · CISA US

v3.17.7highAV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Lsecondary · FSTEC (BDU) RU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 3.9 · impact 5.9

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-287USprimaryCWE-264USCWE-284USCWE-284US

affected products (5)

Products and version ranges known to be affected.

Modicon M221 all references: all versions prior to firmware v1.6.2.0all versionscisa_csaf_otUS
Schneider Electric Software, LLC Modicon M221 all references< 1.6.2.0cisa_csaf_otUS
Schneider Electric SE Modicon M221, all references, all versions prior to firmware V1.6.2.0≤ Modicon M221, all references, all versions prior to firmware V1.6.2.0enisa_euvdEU
Schneider Electric Modicon M221≤ 1.6.2.0fstec_bduRU
schneider-electric modicon m221 firmware< 1.6.2.0nvdUScpe:2.3:o:schneider-electric:modicon_m221_firmware:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

ICSA-18-240-01Schneider Electric Modicon M2212018-08-28icsa · cisa_csaf_otUS
Successful exploitation of these vulnerabilities may allow unauthorized users to replay authentication sequences, overwrite passwords, or decode passwords.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisa_csaf_ot nvd NVD CVE.org MITRE

published 2018-08-29modified 2026-06-17

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references (6)

External citations — patches, advisories, analysis.

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