# CVE-2023-20244

## Summary

- **CVE ID:** CVE-2023-20244
- **Severity:** HIGH
- **CVSS Score:** 8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H)
- **CWE:** CWE-771
- **Published:** Nov 1, 2023
- **Last Modified:** Mar 13, 2026

## Description

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.

## Affected Products

- Cisco — Cisco Firepower Threat Defense Software (6.2.3)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.1)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.2)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.3)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.4)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.5)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.6)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.7)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.8)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.10)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.11)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.9)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.12)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.13)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.14)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.15)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.16)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.17)
- Cisco — Cisco Firepower Threat Defense Software (6.2.3.18)
- Cisco — Cisco Firepower Threat Defense Software (6.6.0)
- Cisco — Cisco Firepower Threat Defense Software (6.6.0.1)
- Cisco — Cisco Firepower Threat Defense Software (6.6.1)
- Cisco — Cisco Firepower Threat Defense Software (6.6.3)
- Cisco — Cisco Firepower Threat Defense Software (6.6.4)
- Cisco — Cisco Firepower Threat Defense Software (6.6.5)
- Cisco — Cisco Firepower Threat Defense Software (6.6.5.1)
- Cisco — Cisco Firepower Threat Defense Software (6.6.5.2)
- Cisco — Cisco Firepower Threat Defense Software (6.6.7)
- Cisco — Cisco Firepower Threat Defense Software (6.6.7.1)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.1)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.3)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.2)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.4)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.5)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.6)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.7)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.8)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.9)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.10)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.11)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.12)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.13)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.14)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.15)
- Cisco — Cisco Firepower Threat Defense Software (6.4.0.16)
- Cisco — Cisco Firepower Threat Defense Software (6.7.0)
- Cisco — Cisco Firepower Threat Defense Software (6.7.0.1)
- Cisco — Cisco Firepower Threat Defense Software (6.7.0.2)
- Cisco — Cisco Firepower Threat Defense Software (6.7.0.3)
- Cisco — Cisco Firepower Threat Defense Software (7.0.0)
- Cisco — Cisco Firepower Threat Defense Software (7.0.0.1)
- Cisco — Cisco Firepower Threat Defense Software (7.0.1)
- Cisco — Cisco Firepower Threat Defense Software (7.0.1.1)
- Cisco — Cisco Firepower Threat Defense Software (7.0.2)
- Cisco — Cisco Firepower Threat Defense Software (7.0.2.1)
- Cisco — Cisco Firepower Threat Defense Software (7.0.3)
- Cisco — Cisco Firepower Threat Defense Software (7.0.4)
- Cisco — Cisco Firepower Threat Defense Software (7.0.5)
- Cisco — Cisco Firepower Threat Defense Software (7.1.0)
- Cisco — Cisco Firepower Threat Defense Software (7.1.0.1)
- Cisco — Cisco Firepower Threat Defense Software (7.1.0.3)
- Cisco — Cisco Firepower Threat Defense Software (7.2.0)
- Cisco — Cisco Firepower Threat Defense Software (7.2.0.1)
- Cisco — Cisco Firepower Threat Defense Software (7.2.1)
- Cisco — Cisco Firepower Threat Defense Software (7.2.2)
- Cisco — Cisco Firepower Threat Defense Software (7.2.3)
- Cisco — Cisco Firepower Threat Defense Software (7.3.0)
- Cisco — Cisco Firepower Threat Defense Software (7.3.1)
- Cisco — Cisco Firepower Threat Defense Software (7.3.1.1)

## References

- [CNA](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-intrusion-dos-DfT7wyGC)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.17%
- **EPSS Percentile:** 37.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._