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Firepower Threat Defense Software CVE-2024-20339

HIGH
NULL Pointer Dereference (CWE-476)
2024-10-23 psirt@cisco.com
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could crash the application by dereferencing a null pointer by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.7% exploitation probability (EPSS)

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AnalysisAI

A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Check pointers before dereferencing. Use static analysis tools to detect null pointer paths.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as NULL Pointer Dereference (CWE-476), which allows attackers to crash the application by dereferencing a null pointer. A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an issue that occurs when TLS traffic is processed. An attacker could exploit this vulnerability by sending certain TLS traffic over IPv4 through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition and impacting traffic to and through the affected device. Affected products include: Cisco Firepower Threat Defense Software.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to an issue that occurs when TLS traffic is processed. An attacker could exploit this vulnerability by sending certain TLS traffic over IPv4 through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition and impacting traffic to and through the affected device.

Threat Intelligence Overview

EPSS Score
0.7%
Top 51% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.7%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.1:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.2:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.3:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.4:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.5:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.6:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.7:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.8:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.9:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.10:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.11:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.12:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.13:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.14:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.15:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.16:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.17:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.2.3.18:*:*:*:*:*:*:*
cpe:2.3:a:cisco:firepower_threat_defense_software:6.4.0:*:*:*:*:*:*:*
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