Evidence used
- No CISA KEV confirmation is currently recorded.
- Exploitation requires an existing local or physical foothold with privileges.
- EPSS is 0.18% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2024
CVE-2023-32737High confidence
A vulnerability has been identified in SIMATIC STEP 7 Safety V18 (All versions < V18 Update 2)
Siemens · SIMATIC STEP 7 Safety V18
Official source article: Siemens SSA-313039 ↗. Check the applicable product and release in the original source.
7.0HighCVSS 4.0
Patch only the product branches with a verified fix
Fix availability varies by productHigh technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Medium, lowered one band.downgradedsince 27 Aug 2025
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
- Confirm that the asset runs Siemens SIMATIC STEP 7 Safety V18 and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Siemens ProductCERT: 1 affected or under-investigation product state without a fixed product state in the same current advisory
Direct vendor intelligence
1 currentAuthoritative 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.
SSA-313039 · CSAF 2.0 · revision 1 · finalSiemens ProductCERTSSA-313039: Deserialization Vulnerability in STEP 7 Safety before V19
The vendor explicitly identifies these products as affected by this CVE.
- SIMATIC STEP 7 Safety V18
- Summary
- Affected applications do not properly restrict the .NET BinaryFormatter when deserializing user-controllable input. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application. This is the same issue that exists for .NET BinaryFormatter https://docs.microsoft.com/en-us/visualstudio/code-quality/ca2300.
- Remediation
- Update to V18 Update 2 or later version
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
A vulnerability has been identified in SIMATIC STEP 7 Safety V18 (All versions < V18 Update 2). Affected applications do not properly restrict the .NET BinaryFormatter when deserializing user-controllable input. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application. This is the same issue that exists for .NET BinaryFormatter https://docs.microsoft.com/en-us/visualstudio/code-quality/ca2300.
What
A vulnerability has been identified in SIMATIC STEP 7 Safety V18 (All versions < V18 Update 2). Affected applications do not properly restrict the .NET BinaryFormatter when deserializing user-controllable input. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application. This is the same issue that exists for .NET BinaryFormatter https://docs.microsoft.com/en-us/visualstudio/code-quality/ca2300.
Why
Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.
How
An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may execute code or commands in the affected security context.
What
A vulnerability has been identified in SIMATIC STEP 7 Safety V18 (All versions < V18 Update 2). Affected applications do not properly restrict the .NET BinaryFormatter when deserializing user-controllable input. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application. This is the same issue that exists for .NET BinaryFormatter https://docs.microsoft.com/en-us/visualstudio/code-quality/ca2300.
Why
Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.
How
An attacker operating through local access may attempt exploitation with elevated privileges. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 → Deserialization of Untrusted Data → execute code or commands in the affected security context
- Attack surface
- Local
- Privileges required
- High: elevated access is required
- User interaction
- Passive interaction required
- 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-502 ↗
CWE-502: Deserialization of Untrusted Data. The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
- 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:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCommon 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.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UIPassiveUser interaction: A user must unknowingly interact with the vulnerable system.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.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
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
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
- SIMATIC STEP 7 Safety V18
- 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 Jul 2024 · Last source change 27 Aug 2025, 20:32 UTC · CWE-502 · Deserialization of Untrusted Data
CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2023-36962
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
View recent updates ↗What changed after publication
- Remediation statusRemediation status changed from Awaiting fix to Mitigation available.Siemens ProductCERT ↗
- Before
- Awaiting fix
- After
- Mitigation available
CVE published
Remediation guidance recorded
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.