CVE-2021-25661

mediumpriority · track · 30EPSS 0.011 · 67 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.15% (67th) EPSS
CVSS 5 · medium
Is it mine?
72 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · cisa_csaf_ot · siemens_psirt

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:Csecondary · CISA US
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondaryexploitability 3.9 · impact 3.6
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H/E:P/RL:O/RC:Csecondary · Siemens ProductCERT DE
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-788USCWE-788USCWE-788US
05

affected products (72)

Products and version ranges known to be affected.

showing 20 of 72
06

advisories (2)

Vendor and ecosystem advisories describing this.

  • SSA-538778SSA-538778: SmartVNC Vulnerabilities in SIMATIC HMI/WinCC Products2021-05-11csaf · siemens_psirtDE

    Multiple SmartVNC vulnerabilities in the affected products listed below could allow remote code execution and Denial-of-Service attacks under certain conditions. Siemens has released updates for the affected products and recommends to update to the latest version.

  • ICSA-21-131-12Siemens SIMATIC SmartVNC HMI WinCC Products (Update B)2021-05-11icsa · cisa_csaf_otUS

    Multiple SmartVNC vulnerabilities in the affected products listed below could allow remote code execution and Denial-of-Service attacks under certain conditions. Siemens has released updates for the affected products and recommends to update to the latest version.

07

also known as (3)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdcisa_csaf_otsiemens_psirtNVDCVE.orgMITRE
published 2021-05-12modified 2026-06-17
09

references (9)

External citations — patches, advisories, analysis.

scry

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