CVE intelligence and bounded remediation

CVE-2023-20244 — Cisco Firepower Threat Defense security vulnerability

High CVSS 8.6

A vulnerability in the internal packet processing of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Firewalls could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of certain packets when they are sent to the inspection engine. An attacker could exploit this vulnerability by sending a series of crafted packets to an affected device. A successful exploit could allow the attacker to deplete all 9,472 byte blocks on the device, resulting in traffic loss across the device or an unexpected reload of the device. If the device does not reload on its own, a manual reload of the device would be required to recover from this state.

Severity
High
CVSS
8.6 (3.1)
Published
2023-11-01
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-771

Affected products

  • cisco / firepower_threat_defense / 6.2.3
  • cisco / firepower_threat_defense / 6.2.3.1
  • cisco / firepower_threat_defense / 6.2.3.2
  • cisco / firepower_threat_defense / 6.2.3.3
  • cisco / firepower_threat_defense / 6.2.3.4
  • cisco / firepower_threat_defense / 6.2.3.5

Showing 6 representative product identities from 70 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

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