Cyber Resilience

CVE-2021-27383

HighDDoSUpdated

Published: 12 May 2021

Published
12 May 2021
Modified
02 June 2026
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0059 69.7th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-27383 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Siemens Simatic Hmi Comfort Outdoor Panels 15\" Firmware. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 30.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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 a heap allocation leak vulnerability in the server Tight encoder, which could result in a Denial-of-Service condition.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

siemens
simatic wincc runtime advanced
15.1, 16 · ≤ 16 · ≤ 15.1
siemens
sinamics sh150 firmware
all versions
siemens
sinamics sm150i firmware
all versions
siemens
sinamics gh150 firmware
all versions
siemens
sinamics gl150 firmware
all versions
siemens
sinamics gm150 firmware
all versions
siemens
sinamics sl150 firmware
all versions
siemens
sinamics sm120 firmware
all versions
siemens
sinamics sm150 firmware
all versions
siemens
simatic hmi comfort outdoor panels 7\" firmware
15.1, 16 · ≤ 16 · ≤ 15.1
+8 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-770

This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.

addresses: CWE-770

Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.

addresses: CWE-770

Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.

addresses: CWE-770

Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.

addresses: CWE-770

Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.

addresses: CWE-770

Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.

addresses: CWE-770

Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.

addresses: CWE-770

Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.

References