CVE-2020-7538: n/a PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) — Improper Check for Unusual or Exceptional Conditions

Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available

What, why and how

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) that could cause a crash of the PLC simulator present in EcoStruxureª Control Expert software when receiving a specially crafted request over Modbus.

What

Why

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

Why

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: a network path → Improper Check for Unusual or Exceptional Conditions → disrupt the affected service
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-754 ↗
CWE-754: Improper Check for Unusual or Exceptional Conditions. The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

NetworkUnauthenticatedDenial of serviceCWE-754

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2020-28663Official EUVD mapping

0 linked advisory records.

Official EUVD record

CERT-FR · French · CERTFR-2020-AVI-726Multiples vulnérabilités dans les produits Schneider Electric

de sécurité Schneider Electric SEVD-2020-315-05 du 11 novembre 2020 https://www.se.com/ww/en/download/document/SEVD-2020-315-05/ Bulletin de sécurité Schneider Electric SEVD-2020-315-06 du 11 novembre 2020 https://www.se.com/ww/en/download/document/SEVD-2020-315-06/ Bulletin de sécurité Schneider Electric SEVD-2020-315-07 du 11 novembre 2020 https://www.se.com/ww/en/download/document/SEVD-2020-315-07/ Référence CVE CVE-2020-28211 https://www.cve.org/CVERecord?id=CVE-2020-28211 Référence CVE CVE-2020-28212 https://www.cve.org/CVERecord?id=CVE-2020-28212 Référence CVE CVE-2020-28213 https://www.cve.org/CVERecord?id=CVE-2020-28213 Référence CVE CVE-2020-7538 https://www.cve.org/CVERecord?id=CVE-2020-7538 Référence CVE CVE-2020-7544 https://www.cve.org/CVERecord?id=CVE-2020-7544 Référence CVE CVE-2020-7550 https://www.cve.org/CVERecord?id=CVE-2020-7550 Référence CVE CVE-2020-7551 https://www.cve.org/CVERecord?id=CVE-2020-7551 Référence CVE CVE-2020-7552 https://www.cve.org/CVERecord?id=CVE-2020-7552 Référence CVE CVE-2020-7553 https://www.cve.org/CVERecord?id=CVE-2020-7553 Référence CVE CVE-2020-7554 https://www.cve.org/CVERecord?id=CVE-2020-7554 Référence CVE CVE-2020-7555 https://www.cve.org/CVERecord?id=CVE-2020-7555 Référence CVE CVE-2020-7556 https://www.cve.org/CVERecord?id=CVE-2020-7556 Ré

Official advisory

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: Schneider Electric PLC Simulator for EcoStruxure™ Control Expert prior to v15.0 SP1; Schneider Electric PLC Simulator for Unity Pro (former name of EcoStruxure™ Control Expert) all versions; Schneider Electric PLC Simulator for EcoStruxure™ Process Expert all versions
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: EcoStruxure™ Control Expert Version 15.0 SP1 product includes a fix for the vulnerability CVE-2020-7559 and is available for download here: https://www.se.com/ww/en/download/document/EcoStruxureControlExpert_15SP1 Customers should use appropriate patching methodologies when applying these patches to their systems. We strongly recommend the use of back-ups and evaluating the impact of these patches in a Test and Development environment or on an offline infrastructure. Contact Schneider Electric’s Customer Care Center if you need assistance removing a patch. If customers choose not to apply the remediation provided above, they should immediately follow the recommendations in the Mitigation section below to reduce the risk of exploit.
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 19 Nov 2020 · Last source change 4 Aug 2024, 09:33 UTC · CWE-754 · Improper Check for Unusual or Exceptional Conditions

CVE recordCVE.org · 5.1

CVSS sourceNIST NVD

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2020-28663

Product sourceVendor CSAF · Schneider Electric CPCERT

Remediation sourceVendor CSAF · Schneider Electric CPCERT

CWE sourceCNA

NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

2020-11-19CVE published

2024-08-04Fixed release or patch reference recorded

ENISA EUVD · EUVD-2020-28663↗Vendor CSAF · Schneider Electric CPCERT↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

n/a PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) — Improper Check for Unusual or Exceptional Conditions

Authoritative vendor CSAF and VEX advisories

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2020-28663

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication

n/a PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) — Improper Check for Unusual or Exceptional Conditions

National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

EUVD-2020-28663

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.