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Fencer Vulns
high 7.5

CVE-2021-25660 json

A vulnerability has been identified in SIMATIC HMI Comfort Outdoor Panels V15 7\" & 15\" (incl.

published 2021-05-12 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-12552

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

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 server side when sending data from the client, which could result in a Denial-of-Service condition.

Patch / fix

  • siemens simatic_wincc_runtime_advanced 15.1, 16
  • siemens simatic_hmi_comfort_outdoor_panels_7"_firmware 15.1, 16
  • siemens simatic_hmi_comfort_outdoor_panels_15"_firmware 15.1, 16
  • siemens simatic_hmi_comfort_panels_4"_firmware 15.1, 16
  • siemens simatic_hmi_comfort_panels_22"_firmware 15.1, 16
  • siemens simatic_hmi_ktp_mobile_panels_ktp400f_firmware 15.1, 16
  • siemens simatic_hmi_ktp_mobile_panels_ktp700_firmware 15.1, 16
  • siemens simatic_hmi_ktp_mobile_panels_ktp700f_firmware 15.1, 16
  • siemens simatic_hmi_ktp_mobile_panels_ktp900_firmware 15.1, 16
  • siemens simatic_hmi_ktp_mobile_panels_ktp900f_firmware 15.1, 16

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-131-12 updated cvss 5.4

Siemens SIMATIC SmartVNC HMI WinCC Products (Update B)

  • Siemens SIMATIC HMI Comfort Outdoor Panels V15 7" & 15" (incl. SIPLUS variants) <V15.1_Update_6
    affected: fixed in V15.1, mitigation support.industry.siemens.com
  • Siemens SIMATIC HMI Comfort Outdoor Panels V16 7" & 15" (incl. SIPLUS variants) <V16_Update_4
    affected: fixed in V16, mitigation support.industry.siemens.com
  • Siemens SIMATIC HMI Comfort Panels V15 4" - 22" (incl. SIPLUS variants) <V15.1_Update_6
    affected: fixed in V15.1, mitigation support.industry.siemens.com
  • Siemens SIMATIC HMI Comfort Panels V16 4" - 22" (incl. SIPLUS variants) <V16_Update_4
    affected: fixed in V16, mitigation support.industry.siemens.com
  • Siemens SIMATIC HMI KTP Mobile Panels V15 KTP400F, KTP700, KTP700F, KTP900 and KTP900F <V15.1_Update_6
    affected: fixed in V15.1, mitigation support.industry.siemens.com
  • Siemens SIMATIC HMI KTP Mobile Panels V16 KTP400F, KTP700, KTP700F, KTP900 and KTP900F <V16_Update_4
    affected: fixed in V16, mitigation support.industry.siemens.com
  • Siemens SIMATIC WinCC Runtime Advanced V15 <V15.1_Update_6
    affected: fixed in V15.1, mitigation support.industry.siemens.com
  • Siemens SIMATIC WinCC Runtime Advanced V16 <V16_Update_4
    affected: fixed in V16, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.99% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • 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
  • Siemens SIMATIC WinCC Runtime Advanced V15
  • Siemens SIMATIC WinCC Runtime Advanced V16

Classification

Weakness
  • CWE-788 Access of Memory Location After End of Buffer
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.