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Vulnerability record · CVE-2021-25661 · published 12 May 2021

CVE-2021-25661: Siemens simatic wincc runtime advanced vulnerability

Siemens · Simatic Wincc Runtime Advanced

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). SmartVNC has an out-of-bounds memory access vulnerability that could be triggered on the client side when sending data from the server, which could result in a Denial-of-Service condition.

7.5 CVSS 3.1 High EPSS 1.1% · top 34.5% CWE-788 · CWE-788
7.5CVSS 3.1 base score, v2 5.0
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
10Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

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). SmartVNC has an out-of-bounds memory access vulnerability that could be triggered on the client side when sending data from the server, which could result in a Denial-of-Service condition.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

10 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf Vendor Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-131-12 Third Party AdvisoryUS Government Resource
https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf Vendor Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-131-12 Third Party AdvisoryUS Government Resource

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-27384Siemens simatic wincc runtime advanced vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIM…EPSS 2.6%9.1CVE-2019-6572Siemens simatic hmi comfort panels firmware information exposure vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Panels 4" - 22" (All versions < V15.1 Update 1), SIMATIC HMI Comfort Outdoor Panels 7" & 1…EPSS 2.7%8.8CVE-2018-13814Siemens simatic hmi comfort panels firmware improper input validation vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Panels 4" - 22" (All versions < V14), SIMATIC HMI Comfort Outdoor Panels 7" & 15" (All ver…EPSS 1.7%8.1CVE-2018-13813Siemens simatic hmi comfort panels firmware open redirect vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Panels 4" - 22" (All versions < V15 Update 4), SIMATIC HMI Comfort Outdoor Panels 7" & 15"…EPSS 1.7%7.5CVE-2021-25660Siemens simatic hmi comfort outdoor panels 7\" firmware memory buffer overflow vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIM…EPSS 0.97%7.5CVE-2021-25662Siemens simatic wincc runtime advanced vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIM…EPSS 1.6%7.5CVE-2021-27383Siemens simatic wincc runtime advanced allocation without limits vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIM…EPSS 1.8%7.5CVE-2021-27385Siemens simatic wincc runtime advanced uncontrolled resource consumption vulnerabilityA vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl. SIPLUS variants) (All versions < V15.1 Update 6), SIM…EPSS 2.6%

Source: NIST National Vulnerability Database (record CVE-2021-25661), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.