CVE intelligence and bounded remediation

CVE-2020-7539 — Schneider-Electric Modicon M340 Bmxp341000 Firmware security vulnerability

High CVSS 7.5

A CWE-754 Improper Check for Unusual or Exceptional Conditions vulnerability exists in the Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions), that could cause a denial of service vulnerability when a specially crafted packet is sent to the controller over HTTP.

Severity
High
CVSS
7.5 (3.1)
Published
2020-12-11
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-754

Affected products

  • schneider-electric / modicon_m340_bmxp341000_firmware
  • schneider-electric / modicon_m340_bmxp342000_firmware
  • schneider-electric / modicon_m340_bmxp3420102_firmware
  • schneider-electric / modicon_m340_bmxp3420102cl_firmware
  • schneider-electric / modicon_m340_bmxp342020_firmware
  • schneider-electric / modicon_m340_bmxp3420302_firmware

Showing 6 representative product identities from 20 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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