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Full vulnerability report · 2021
CVE-2021-29241High confidence

CODESYS Gateway 3 before 3.5.16.70 has a NULL pointer dereference that may result in a denial of service (DoS)

Unknown · Unknown

7.5HighCVSS 3.1
Recommended action
Within 7 days

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

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 1.43% 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.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Unknown Unknown 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 30 daysRemediation target: Within 180 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-2022-011-06 · CSAF 2.0 · revision 7.0.0 · finalSchneider Electric CPCERTCODESYS V3 Runtime, Development System, and Gateway Vulnerabilities
6 known affected

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

  • Schneider Electric Eurotherm E+PLC tools version 1.3.0.1 and prior
  • Schneider Electric M241/M251 versions prior to 5.1.9.34
  • Schneider Electric Easy Harmony ET6 (HMIET Series) - Vijeo Designer Basic version 1.2.1 Hotfix 3 and later
  • Schneider Electric Easy Harmony GXU (HMIGXU Series) - Vijeo Designer Basic version 1.2.1 Hotfix 3 and later
  • Schneider Electric Harmony/ Magelis HMISTU Series - Vijeo Designer Basic version 6.2 SP11 Hotfix 3 and prior
  • Schneider Electric Harmony/ Magelis HMISCU Series - Vijeo Designer Basic Harmony/ Magelis HMISCU Series versions prior to 2.0.3
Summary
Codesys have released a series of vulnerabilities affecting the Codesys Runtime, Development System and Gateway components. Additional details on these vulnerabilities can be found in the CODESYS advisories linked above.
Remediation
Version V1.4.0.0 of the E+PLC Tools software is available and includes a fix for these vulnerabilities. Access to the patch can be obtained through the Eurotherm support team
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-2021-15880

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; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

CODESYS Gateway 3 before 3.5.16.70 has a NULL pointer dereference that may result in a denial of service (DoS).

What

CODESYS Gateway 3 before 3.5.16.70 has a NULL pointer dereference that may result in a denial of service (DoS).

Why

The product dereferences a pointer that it expects to be valid but is NULL.

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

CODESYS Gateway 3 before 3.5.16.70 has a NULL pointer dereference that may result in a denial of service (DoS).

Why

The product dereferences a pointer that it expects to be valid but is NULL.

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.
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 → NULL Pointer Dereference → 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-476 ↗

CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.

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-476
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-20210505Security Bulletin 05 May 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 05 May 2021, published on 5 May 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0297Multiples vulnérabilités dans les produits Schneider Electric

De multiples vulnérabilités ont été découvertes dans les produits Schneider Electric. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, un déni de service à distance et une atteinte à l'intégrité des données.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-628Multiples vulnérabilités dans les produits Schneider Electric

d?id=CVE-2021-21868 Référence CVE CVE-2021-21869 https://www.cve.org/CVERecord?id=CVE-2021-21869 Référence CVE CVE-2021-22778 https://www.cve.org/CVERecord?id=CVE-2021-22778 Référence CVE CVE-2021-22779 https://www.cve.org/CVERecord?id=CVE-2021-22779 Référence CVE CVE-2021-22780 https://www.cve.org/CVERecord?id=CVE-2021-22780 Référence CVE CVE-2021-22781 https://www.cve.org/CVERecord?id=CVE-2021-22781 Référence CVE CVE-2021-22782 https://www.cve.org/CVERecord?id=CVE-2021-22782 Référence CVE CVE-2021-22797 https://www.cve.org/CVERecord?id=CVE-2021-22797 Référence CVE CVE-2021-29240 https://www.cve.org/CVERecord?id=CVE-2021-29240 Référence CVE CVE-2021-29241 https://www.cve.org/CVERecord?id=CVE-2021-29241 Référence CVE CVE-2021-33485 https://www.cve.org/CVERecord?id=CVE-2021-33485 Référence CVE CVE-2022-0715 https://www.cve.org/CVERecord?id=CVE-2022-0715 Référence CVE CVE-2022-22805 https://www.cve.org/CVERecord?id=CVE-2022-22805 Référence CVE CVE-2022-22806 https://www.cve.org/CVERecord?id=CVE-2022-22806 Référence CVE CVE-2022-2329 https://www.cve.org/CVERecord?id=CVE-2022-2329 Référence CVE CVE-2022-24324 https://www.cve.org/CVERecord?id=CVE-2022-24324 Référence CVE CVE-2022-26507 https://www.cve.org/CVERecord?id=CVE-2022-26507 Référence CVE CVE-2022-34753 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-017Multiples vulnérabilités dans les produits Schneider

rd?id=CVE-2020-8597 Référence CVE CVE-2021-21863 https://www.cve.org/CVERecord?id=CVE-2021-21863 Référence CVE CVE-2021-21864 https://www.cve.org/CVERecord?id=CVE-2021-21864 Référence CVE CVE-2021-21865 https://www.cve.org/CVERecord?id=CVE-2021-21865 Référence CVE CVE-2021-21866 https://www.cve.org/CVERecord?id=CVE-2021-21866 Référence CVE CVE-2021-21867 https://www.cve.org/CVERecord?id=CVE-2021-21867 Référence CVE CVE-2021-21868 https://www.cve.org/CVERecord?id=CVE-2021-21868 Référence CVE CVE-2021-21869 https://www.cve.org/CVERecord?id=CVE-2021-21869 Référence CVE CVE-2021-29240 https://www.cve.org/CVERecord?id=CVE-2021-29240 Référence CVE CVE-2021-29241 https://www.cve.org/CVERecord?id=CVE-2021-29241 Référence CVE CVE-2021-30061 https://www.cve.org/CVERecord?id=CVE-2021-30061 Référence CVE CVE-2021-30062 https://www.cve.org/CVERecord?id=CVE-2021-30062 Référence CVE CVE-2021-30063 https://www.cve.org/CVERecord?id=CVE-2021-30063 Référence CVE CVE-2021-30064 https://www.cve.org/CVERecord?id=CVE-2021-30064 Référence CVE CVE-2021-30065 https://www.cve.org/CVERecord?id=CVE-2021-30065 Référence CVE CVE-2021-30066 https://www.cve.org/CVERecord?id=CVE-2021-30066 Référence CVE CVE-2021-33485 https://www.cve.org/CVERecord?id=CVE-2021-33485 Référence CVE CVE-2022-22722 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-006713CODESYS Gateway における NULL ポインタデリファレンスに関する脆弱性

CODESYS Gateway には、NULL ポインタデリファレンスに関する脆弱性が存在します。

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
Fixed
Action
Version V1.4.0.0 of the E+PLC Tools software is available and includes a fix for these vulnerabilities. Access to the patch can be obtained through the Eurotherm support team
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 3 May 2021 · Last source change 29 May 2026, 14:01 UTC · CWE-476 · NULL Pointer Dereference

CVE recordCVE.org · 5.2
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-2021-15880
Product sourceVendor CSAF · Schneider Electric CPCERT
Remediation sourceVendor CSAF · Schneider Electric CPCERT
CWE sourceCISA ADP
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
    n/a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    n/a · Fixed: Version V1.4.0.0 of the E+PLC Tools software is available and includes a fix for these vulnerabilities. Access to the patch can be obtained through the Eurotherm support team
    Schneider Electric CPCERT ↗
  2. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    Schneider Electric CPCERT ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2021-15880↗Schneider Electric CPCERT security advisory↗CVE authority or vendor reference↗Vendor advisory↗Vendor advisory↗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-2021-29241 · cve.blacktree.nl