CVE-2021-25662

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-05-12 · updated 2026-06-17
Weakness: CWE-755

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 client fails to handle an exception properly if the program execution process is modified after sending a packet from the server, which could result in a Denial-of-Service condition.

Affected products

Siemens Simatic Hmi Comfort Outdoor Panels 15" Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Comfort Outdoor Panels 7" Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Comfort Panels 22" Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Comfort Panels 4" Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Ktp Mobile Panels Ktp400F Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Ktp Mobile Panels Ktp700 Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Ktp Mobile Panels Ktp700F Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Ktp Mobile Panels Ktp900 Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens Simatic Hmi Ktp Mobile Panels Ktp900F Firmware: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16
Siemens SIMATIC WinCC Runtime Advanced: before 16; before 15.1; 16, 16-update1, 16-update2, 16-update3, 15.1, 15.1-update1 (+4) — fixed in 15.1, 16

How to fix

Upgrade to a fixed version: Siemens Simatic Hmi Comfort Outdoor Panels 15" Firmware 15.1, 16; Siemens Simatic Hmi Comfort Outdoor Panels 7" Firmware 15.1, 16; Siemens Simatic Hmi Comfort Panels 22" Firmware 15.1, 16; Siemens Simatic Hmi Comfort Panels 4" 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; Siemens SIMATIC WinCC Runtime Advanced 15.1, 16. Check the vendor advisory for mitigations.

References

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