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Full vulnerability report · 2020
CVE-2020-7559High confidence

n/a PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) — Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Unknown · PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions)

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 4 Aug 2024

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 1.91% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Unknown PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
SEVD-2020-315-07 · CSAF 2.0 · revision 4.0.0 · finalSchneider Electric CPCERTPLC Simulator on EcoStruxure™ Control Expert and Process Expert
1 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • Schneider Electric PLC Simulator for EcoStruxure™ Control Expert prior to v15.0 SP1
Summary
A CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability exists that could cause a crash of the PLC simulator present in EcoStruxure™ Control Expert software and EcoStruxure™ Process Expert when receiving a specially crafted request over Modbus.
Remediation
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.
Optional official sources

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

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-28684

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

A CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') 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

A CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') 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.

Why

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

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

A CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') 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.

Why

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

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.

02

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.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') → 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-120 ↗

CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'). The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

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-120Public exploit reference
A

Official authority intelligence

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

Cyber Security Agency of Singapore · English · CSA-SB-20201125Security Bulletin 25 Nov 2020

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 25 Nov 2020, published on 25 November 2020. Open the linked bulletin for the product, severity and reference information published in that issue.

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

.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 Référence CVE CVE-2020-7557 https://www.cve.org/CVERecord?id=CVE-2020-7557 Référence CVE CVE-2020-7558 https://www.cve.org/CVERecord?id=CVE-2020-7558 Référence CVE CVE-2020-7559 https://www.cve.org/CVERecord?id=CVE-2020-7559 Référence CVE CVE-2020-7561 https://www.cve.org/CVERecord?id=CVE-2020-7561 Référence CVE CVE-2020-7562 https://www.cve.org/CVERecord?id=CVE-2020-7562 Référence CVE CVE-2020-7563 https://www.cve.org/CVERecord?id=CVE-2020-7563 Référence CVE CVE-2020-7564 https://www.cve.org/CVERecord?id=CVE-2020-7564 Référence CVE CVE-2020-7565 https://www.cve.org/CVERecord?id=CVE-2020-7565 Référence CVE CVE-2020-7566 https://www.cve.org/CVERecord?id=CVE-2020-7566 Référence CVE CVE-2020-7567 https://www.cve.org/CVERecord?id=CVE-2020-7567 Référence CVE CVE-2020-7570 https://www.cve.org/CVERecord?id=CVE-2020-7570 Ré

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-009547Schneider Electric 製 PLC Simulator for EcoStruxure Control Expert に複数の脆弱性

PLC Simulator for EcoStruxure Control Expert および PLC Simulator for Unity Pro には、次の複数の脆弱性が存在します。 　* バッファーオーバーフロー (CWE-120) - CVE-2020-7559 　* プログラムの例外的な状態における不適切なチェック (CWE-754) - CVE-2020-7538 　* 不正な認証 (CWE-863) - CVE-2020-28211 　* 過度な認証試行の不適切な制限 (CWE-307) - CVE-2020-28212 　* ダウンロードしたコードの完全性検証不備 (CWE-494) - CVE-2020-28213

Official advisory ↗
03

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
Fixed
Schneider Electric EcoStruxure™ Control Expert 15.0 SP1
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.
04

Evidence and provenance

Published 19 Nov 2020 · Last source change 4 Aug 2024, 09:33 UTC · CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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-2020-28684
Product sourceVendor CSAF · Schneider Electric CPCERT
Remediation sourceVendor CSAF · Schneider Electric CPCERT
CWE sourceCNA
NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (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.
    After
    PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) · Fixed: 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.
    Schneider Electric CPCERT ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2020-28684↗Schneider Electric CPCERT security advisory↗CVE authority or vendor reference↗Public exploit 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.
Free version - for non-commercial use only.CVE-2020-7559 · cve.blacktree.nl