CVE intelligence and bounded remediation

CVE-2021-22787 — Schneider-Electric Modicon M340 Bmxp342020 Firmware security vulnerability

High CVSS 7.5

A CWE-20: Improper Input Validation vulnerability exists that could cause denial of service of the device when an attacker sends a specially crafted HTTP request to the web server of the device. Affected Product: Modicon M340 CPUs: BMXP34 (Versions prior to V3.40), Modicon M340 X80 Ethernet Communication Modules: BMXNOE0100 (H), BMXNOE0110 (H), BMXNOC0401, BMXNOR0200H RTU (All Versions), Modicon Premium Processors with integrated Ethernet (Copro): TSXP574634, TSXP575634, TSXP576634 (All Versions), Modicon Quantum Processors with Integrated Ethernet (Copro): 140CPU65xxxxx (All Versions), Modicon Quantum Communication Modules: 140NOE771x1, 140NOC78x00, 140NOC77101 (All Versions), Modicon Premium Communication Modules: TSXETY4103, TSXETY5103 (All Versions)

Severity
High
CVSS
7.5 (3.1)
Published
2022-02-11
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-20

Affected products

  • schneider-electric / modicon_m340_bmxp342020_firmware
  • schneider-electric / bmxnoe0100_firmware
  • schneider-electric / bmxnoe0110_firmware
  • schneider-electric / bmxnoc0401_firmware
  • schneider-electric / bmxnor0200h_rtu_firmware
  • schneider-electric / tsxp574634_firmware

Showing 6 representative product identities from 14 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

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

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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