CVE intelligence and bounded remediation

CVE-2021-22800 — Schneider-Electric Modicon M218 Firmware security vulnerability

High CVSS 7.5

A CWE-20: Improper Input Validation vulnerability exists that could cause a Denial of Service when a crafted packet is sent to the controller over network port 1105/TCP. Affected Product: Modicon M218 Logic Controller (V5.1.0.6 and prior)

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_m218_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

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