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Full vulnerability report · 2024
CVE-2023-50821High confidence

Siemens SIMATIC PCS 7 V9.1 — Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Siemens · SIMATIC PCS 7 V9.1

Official source article: Siemens SSA-730482 ↗. Check the applicable product and release in the original source.

6.9MediumCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 6 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.18% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Siemens SIMATIC PCS 7 V9.1 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: As exposure requiresRemediation target: Within 365 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.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 6 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

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
SSA-730482 · CSAF 2.0 · revision 3 · interimSiemens ProductCERTSSA-730482: Denial of Service Vulnerability in SIMATIC WinCC
6 known affected

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

  • SIMATIC PCS 7 V9.1
  • SIMATIC WinCC Runtime Professional V17
  • SIMATIC WinCC Runtime Professional V18
  • SIMATIC WinCC Runtime Professional V19
  • SIMATIC WinCC V7.5
  • SIMATIC WinCC V8.0
Summary
The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service condition.
Remediation
Update to V17 Update 8 or later version
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-2023-55554

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 actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 6 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

A vulnerability has been identified in SIMATIC PCS 7 V9.1 (All versions < V9.1 SP2 UC04), SIMATIC WinCC Runtime Professional V17 (All versions < V17 Update 8), SIMATIC WinCC Runtime Professional V18 (All versions < V18 Update 4), SIMATIC WinCC Runtime Professional V19 (All versions < V19 Update 1), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 16), SIMATIC WinCC V8.0 (All versions < V8.0 Update 5). The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service condition.

What

A vulnerability has been identified in SIMATIC PCS 7 V9.1 (All versions < V9.1 SP2 UC04), SIMATIC WinCC Runtime Professional V17 (All versions < V17 Update 8), SIMATIC WinCC Runtime Professional V18 (All versions < V18 Update 4), SIMATIC WinCC Runtime Professional V19 (All versions < V19 Update 1), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 16), SIMATIC WinCC V8.0 (All versions < V8.0 Update 5). The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service condition.

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 local access may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

A vulnerability has been identified in SIMATIC PCS 7 V9.1 (All versions < V9.1 SP2 UC04), SIMATIC WinCC Runtime Professional V17 (All versions < V17 Update 8), SIMATIC WinCC Runtime Professional V18 (All versions < V18 Update 4), SIMATIC WinCC Runtime Professional V19 (All versions < V19 Update 1), SIMATIC WinCC V7.5 (All versions < V7.5 SP2 Update 16), SIMATIC WinCC V8.0 (All versions < V8.0 Update 5). The affected products do not properly validate the input provided in the login dialog box. An attacker could leverage this vulnerability to cause a persistent denial of service condition.

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 local access 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
local access → Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') → disrupt the affected service
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
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:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedDenial of serviceCWE-120
A

Official authority intelligence

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

BSI · German · WID-SEC-2024-0817Siemens SIMATIC WinCC: Schwachstelle ermöglicht Denial of Service

Ein lokaler Angreifer kann eine Schwachstelle in Siemens SIMATIC WinCC ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20240410Security Bulletin 10 Apr 2024

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Apr 2024, published on 10 April 2024. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0281Multiples vulnérabilités dans les produits Siemens

De multiples vulnérabilités ont été découvertes dans les produits Siemens . Certaines d'entre elles permettent à un attaquant de provoquer une élévation de privilèges, un déni de service à distance et une exécution de code arbitraire à distance.

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.
Fix availability varies by product
Affected
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 9 Apr 2024 · Last source change 26 Feb 2025, 18:41 UTC · CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVE recordCVE.org · 5.1
CVSS sourceCNA
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-2023-55554
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceCNA
NVD statusNVD not scheduled

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Siemens ProductCERT ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2023-55554↗CVE authority or vendor reference · Siemens SSA-730482↗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-2023-50821 · cve.blacktree.nl