HOMEVULNERABILITIESCVE-2021-27384
CRITICAL

CVE-2021-27384

CWE-788Published: May 12, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-27384 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

siemens35 product(s)
simatic wincc runtime advancedsinamics sh150 firmwaresinamics sh150sinamics sm150i firmwaresinamics sm150isinamics gh150 firmwaresinamics gh150sinamics gl150 firmwaresinamics gl150sinamics gm150 firmwaresinamics gm150sinamics sl150 firmware+23
Source: NVD CPE · 55 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdf
PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf
PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdf
PATCHhttps://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-21-131-11
ADVISORYhttps://us-cert.cisa.gov/ics/advisories/icsa-21-131-11

All References (6)

→
https://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdfPatch · Vendor Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdfPatch · Vendor Advisory
→
https://us-cert.cisa.gov/ics/advisories/icsa-21-131-11Third Party Advisory · US Government Resource
→
https://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdfPatch · Vendor Advisory
→
https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdfPatch · Vendor Advisory
→
https://us-cert.cisa.gov/ics/advisories/icsa-21-131-11Third Party Advisory · US Government Resource

Quick Facts

CVE IDCVE-2021-27384
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-788
CISA KEVNo
Affected1 vendor(s)
PublishedMay 12, 2021

Related CVEs (CWE-788)

CVE-2019-8280
9.8
CVE-2019-8266
9.8
CVE-2019-8264
9.8
CVE-2019-8265
9.8
CVE-2021-21104
8.8
CVE-2021-21105
8.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-27384 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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