CVE intelligence and bounded remediation

CVE-2021-37185 — Siemens Simatic Drive Controller Cpu 1504D Tf Firmware security vulnerability

High CVSS 7.5

A vulnerability has been identified in SIMATIC Drive Controller family (All versions >= V2.9.2 < V2.9.4), SIMATIC ET 200SP Open Controller CPU 1515SP PC2 (incl. SIPLUS variants) (All versions >= V21.9 < V21.9.4), SIMATIC S7-1200 CPU family (incl. SIPLUS variants) (All versions >= V4.5.0 < V4.5.2), SIMATIC S7-1500 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions >= V2.9.2 < V2.9.4), SIMATIC S7-1500 Software Controller (All versions >= V21.9 < V21.9.4), SIMATIC S7-PLCSIM Advanced (All versions >= V4.0 < V4.0 SP1), SIPLUS TIM 1531 IRC (All versions < V2.3.6), TIM 1531 IRC (All versions < V2.3.6). An unauthenticated attacker could cause a denial-of-service condition in a PLC when sending specially prepared packets over port 102/tcp. A restart of the affected device is needed to restore normal operations.

Severity
High
CVSS
7.5 (3.1)
Published
2022-02-09
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-672

Affected products

  • siemens / simatic_drive_controller_cpu_1504d_tf_firmware
  • siemens / simatic_drive_controller_cpu_1507d_tf_firmware
  • siemens / simatic_et_200sp_open_controller_cpu_1515sp_pc2_firmware
  • siemens / simatic_s7-plcsim_advanced_firmware
  • siemens / simatic_s7-plcsim_advanced_firmware / 4.0
  • siemens / tim_1531_irc_firmware

Showing 6 representative product identities from 49 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Use-after-free, double free, and expired resource use

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace ownership, references, callbacks, asynchronous tasks, and teardown paths around the affected object or resource.
  • Identify reachable inputs and timing or state transitions that can release the object while references remain.
  • Confirm affected builds, allocators, feature flags, architectures, and process privileges.

Remediate safely

  • Apply the maintained ownership or lifetime fix and rebuild all artifacts containing the affected native code.
  • Use explicit ownership, safe reference management, cancellation and join semantics, and idempotent teardown.
  • Add deterministic lifetime tests plus isolated sanitizer and concurrency coverage for shutdown and error paths.

Authoritative sources

Complete CVE record and remediation plan

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