Siemens SIMATIC WinCC Runtime Advanced V15: Access of Memory Location After End of Buffer (CVE-2021-27384)
Published Sources: CVE.org
What is affected, what to do
A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Outdoor Panels V16 7\" & 15\" (incl.
Update simatic_wincc_runtime_advanced to version 16.
- Affected
- Siemens SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants)
eq All versions < V15.1 Update 6..All versions < V15.1 Update 6 - Siemens SIMATIC HMI Comfort Outdoor Panels V16 7\" & 15\" (incl. SIPLUS variants)
eq All versions < V16 Update 4..All versions < V16 Update 4 - Siemens SIMATIC HMI Comfort Panels V15 4\" - 22\" (incl. SIPLUS variants)
eq All versions < V15.1 Update 6..All versions < V15.1 Update 6 - Siemens SIMATIC HMI Comfort Panels V16 4\" - 22\" (incl. SIPLUS variants)
eq All versions < V16 Update 4..All versions < V16 Update 4 - Siemens SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F
eq All versions < V15.1 Update 6..All versions < V15.1 Update 6 - Siemens SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F
eq All versions < V16 Update 4..All versions < V16 Update 4 - Siemens SIMATIC WinCC Runtime Advanced V15
eq All versions < V15.1 Update 6..All versions < V15.1 Update 6 - Siemens SIMATIC WinCC Runtime Advanced V16
eq All versions < V16 Update 4..All versions < V16 Update 4 - Siemens SINAMICS GH150
eq All versions..All versions - Siemens SINAMICS GL150 (with option X30)
eq All versions..All versions - Siemens SINAMICS GM150 (with option X30)
eq All versions..All versions - Siemens SINAMICS SH150
eq All versions..All versions - Siemens SINAMICS SL150
eq All versions..All versions - Siemens SINAMICS SM120
eq All versions..All versions - Siemens SINAMICS SM150
eq All versions..All versions - Siemens SINAMICS SM150i
eq All versions..All versions
- Siemens SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants)
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Metrics
9.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
9.8
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: CVE.org
2.6 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 85.4
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 107.32 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 9.8 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 9.8
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 2.6 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 85.4
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 2 June 2026
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-788
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Outdoor Panels V16 7\" & 15\" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI Comfort Panels V15 4\" - 22\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIMATIC HMI Comfort Panels V16 4\" - 22\" (incl. SIPLUS variants) (All versions < V16 Update 4), SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V15.1 Update 6), SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F (All versions < V16 Update 4), SIMATIC WinCC Runtime Advanced V15 (All versions < V15.1 Update 6), SIMATIC WinCC Runtime Advanced V16 (All versions < V16 Update 4), SINAMICS GH150 (All versions), SINAMICS GL150 (with option X30) (All versions), SINAMICS GM150 (with option X30) (All versions), SINAMICS SH150 (All versions), SINAMICS SL150 (All versions), SINAMICS SM120 (All versions), SINAMICS SM150 (All versions), SINAMICS SM150i (All versions). SmartVNC has an out-of-bounds memory access vulnerability in the device layout handler, represented by a binary data stream on client side, which can potentially result in code execution.
Source: NVD (NIST), cvelistv5
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Siemens | SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) |
|
|
| Siemens | SIMATIC HMI Comfort Outdoor Panels V16 7\" & 15\" (incl. SIPLUS variants) |
|
|
| Siemens | SIMATIC HMI Comfort Panels V15 4\" - 22\" (incl. SIPLUS variants) |
|
|
| Siemens | SIMATIC HMI Comfort Panels V16 4\" - 22\" (incl. SIPLUS variants) |
|
|
| Siemens | SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F |
|
|
| Siemens | SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F |
|
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| Siemens | SIMATIC WinCC Runtime Advanced V15 |
|
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| Siemens | SIMATIC WinCC Runtime Advanced V16 |
|
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| Siemens | SINAMICS GH150 |
|
|
| Siemens | SINAMICS GL150 (with option X30) |
|
|
| Siemens | SINAMICS GM150 (with option X30) |
|
|
| Siemens | SINAMICS SH150 |
|
|
| Siemens | SINAMICS SL150 |
|
|
| Siemens | SINAMICS SM120 |
|
|
| Siemens | SINAMICS SM150 |
|
|
| Siemens | SINAMICS SM150i |
|
|
| siemens | simatic_wincc_runtime_advanced |
|
|
Vendors and products
- Siemens Simatic HMI Comfort Outdoor Panels 15\" Firmware
- Siemens Simatic HMI Comfort Outdoor Panels 7\" Firmware
- Siemens Simatic HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. Siplus Variants)
- Siemens Simatic HMI Comfort Outdoor Panels V16 7\" & 15\" (incl. Siplus Variants)
- Siemens Simatic HMI Comfort Panels 22\" Firmware
- Siemens Simatic HMI Comfort Panels 4\" Firmware
- Siemens Simatic HMI Comfort Panels V15 4\" - 22\" (incl. Siplus Variants)
- Siemens Simatic HMI Comfort Panels V16 4\" - 22\" (incl. Siplus Variants)
- Siemens Siemens SIMATIC HMI KTP Mobile Panels Ktp400f Firmware
- Siemens Siemens SIMATIC HMI KTP Mobile Panels Ktp700f Firmware
- Siemens Siemens SIMATIC HMI KTP Mobile Panels Ktp700 Firmware
- Siemens Siemens SIMATIC HMI KTP Mobile Panels Ktp900f Firmware
Affected operating systems
| Other | siemens | simatic_hmi_comfort_outdoor_panels_15\"_firmware | 15.1 |
| Other | siemens | simatic_hmi_comfort_outdoor_panels_15\"_firmware | 16 |
| Other | siemens | simatic_hmi_comfort_outdoor_panels_15\"_firmware | — |
| Other | siemens | simatic_hmi_comfort_outdoor_panels_7\"_firmware | 15.1 |
| Other | siemens | simatic_hmi_comfort_outdoor_panels_7\"_firmware | 16 |
| Other | siemens | simatic_hmi_comfort_outdoor_panels_7\"_firmware | — |
| Other | siemens | simatic_hmi_comfort_panels_22\"_firmware | 15.1 |
| Other | siemens | simatic_hmi_comfort_panels_22\"_firmware | 16 |
| Other | siemens | simatic_hmi_comfort_panels_22\"_firmware | — |
| Other | siemens | simatic_hmi_comfort_panels_4\"_firmware | 15.1 |
| Other | siemens | simatic_hmi_comfort_panels_4\"_firmware | 16 |
| Other | siemens | simatic_hmi_comfort_panels_4\"_firmware | — |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp400f_firmware | 15.1 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp400f_firmware | 16 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp400f_firmware | — |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp700_firmware | 15.1 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp700_firmware | 16 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp700_firmware | — |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp700f_firmware | 15.1 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp700f_firmware | 16 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp700f_firmware | — |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp900_firmware | 15.1 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp900_firmware | 16 |
| Other | siemens | simatic_hmi_ktp_mobile_panels_ktp900_firmware | — |
Weakness classes (CWE)
CWE-788Access of Memory Location After End of Buffer
Base
The product reads or writes to a buffer using an index or pointer that references a memory location after the end of the buffer.
Entry at MITRE CWE-788
References & sources
- Siemens ProductCERTproductcert/pdf/ssa-538778.pdfx_refsource_MISC, Patch, Vendor advisory
- Siemens ProductCERTproductcert/pdf/ssa-286838.pdfx_refsource_MISC, Patch, Vendor advisory
- us-cert.cisa.govics/advisories/icsa-21-131-11x_refsource_MISC, Third-party advisory, US government resource
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<a href="https://intel.neosec.eu/en/cve/CVE-2021-27384"><img src="https://intel.neosec.eu/badge/cve/CVE-2021-27384.svg?lang=en" alt="CVE-2021-27384 – NEOSEC Intel" height="20"></a>