CVE intelligence and bounded remediation

CVE-2019-6819 — Schneider-Electric Modicon M340 Firmware security vulnerability

High CVSS 7.5

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists which could cause a possible Denial of Service when specific Modbus frames are sent to the controller in the products: Modicon M340 - firmware versions prior to V3.01, Modicon M580 - firmware versions prior to V2.80, All firmware versions of Modicon Quantum and Modicon Premium.

Severity
High
CVSS
7.5 (3.1)
Published
2019-05-22
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-754

Affected products

  • schneider-electric / modicon_m340_firmware
  • schneider-electric / modicon_m580_firmware
  • schneider-electric / modicon_quantum_firmware
  • schneider-electric / modicon_premium_firmware

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

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.