CVE-2023-20244

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

1.0% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-11-01 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-11 19:33 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.0% in the next 30 days (EPSS).
• Severity: 8.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-11-01 17:15 UTC

Last modified

2026-08-11 19:33 UTC

Exploit probability

1.0% · EPSS, next 30 days

Weakness

CWE-771

Record status

Modified

Affected

• Cisco Secure Firewall Threat Defense 6.2.3
• Cisco Secure Firewall Threat Defense 6.2.3.1
• Cisco Secure Firewall Threat Defense 6.2.3.2
• Cisco Secure Firewall Threat Defense 6.2.3.3
• Cisco Secure Firewall Threat Defense 6.2.3.4
• Cisco Secure Firewall Threat Defense 6.2.3.5
• Cisco Secure Firewall Threat Defense 6.2.3.6
• Cisco Secure Firewall Threat Defense 6.2.3.7

Attack profile CVSS 3.1 · 8.6

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2023-20244.md and follow it. Check whether this project is affected by CVE-2023-20244. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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