CVE-2023-20042

Published Nov 1, 2023 CVSS 3.1 · 6.8 Medium EPSS < 1% KEV · Not listed

Description

A vulnerability in the AnyConnect SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an implementation error within the SSL/TLS session handling process that can prevent the release of a session handler under specific conditions. An attacker could exploit this vulnerability by sending crafted SSL/TLS traffic to an affected device, increasing the probability of session handler leaks. A successful exploit could allow the attacker to eventually deplete the available session handler pool, preventing new sessions from being established and causing a DoS condition.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco Adaptive Security Appliance (ASA) Software

affected

Version	Status	Constraints
`9.16.1`	affected	—
`9.16.1.28`	affected	—
`9.16.2`	affected	—
`9.16.2.3`	affected	—
`9.16.2.7`	affected	—
`9.16.2.11`	affected	—
`9.16.2.13`	affected	—
`9.16.2.14`	affected	—
`9.16.3`	affected	—
`9.16.3.3`	affected	—
`9.16.3.14`	affected	—
`9.16.3.15`	affected	—
`9.16.3.19`	affected	—
`9.16.3.23`	affected	—
`9.16.4`	affected	—
`9.16.4.9`	affected	—
`9.17.1`	affected	—
`9.17.1.7`	affected	—
`9.17.1.9`	affected	—
`9.17.1.10`	affected	—
`9.17.1.11`	affected	—
`9.17.1.13`	affected	—
`9.17.1.15`	affected	—
`9.17.1.20`	affected	—
`9.18.1`	affected	—
`9.18.1.3`	affected	—
`9.18.2`	affected	—
`9.18.2.5`	affected	—
`9.18.2.7`	affected	—
`9.19.1`	affected	—

Cisco

Cisco Firepower Threat Defense Software

affected

Version	Status	Constraints
`7.0.0`	affected	—
`7.0.0.1`	affected	—
`7.0.1`	affected	—
`7.0.1.1`	affected	—
`7.0.2`	affected	—
`7.0.2.1`	affected	—
`7.0.3`	affected	—
`7.0.4`	affected	—
`7.0.5`	affected	—
`7.1.0`	affected	—
`7.1.0.1`	affected	—
`7.1.0.2`	affected	—
`7.1.0.3`	affected	—
`7.2.0`	affected	—
`7.2.0.1`	affected	—
`7.2.1`	affected	—
`7.2.2`	affected	—
`7.2.3`	affected	—
`7.3.0`	affected	—
`7.3.1`	affected	—
`7.3.1.1`	affected	—

Configuration 1 [-]

OR	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.0:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.0.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.1.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.2:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.2.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.3:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.4:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.5:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0.2:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0.3:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.0:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.0.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.2:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.3:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.3.0:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.3.1:::::::*
	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.3.1.1:::::::*

Configuration 2 [-]

OR	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.1:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.1.28:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.2:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.2.3:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.2.7:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.2.11:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.2.13:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.2.14:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.3:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.3.3:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.3.14:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.3.15:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.3.19:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.3.23:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.4:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.16.4.9:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.7:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.9:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.10:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.11:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.13:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.15:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.20:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.1:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.1.3:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.5:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.7:::::::*
	cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1:::::::*

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2023-24221	A vulnerability in the AnyConnect SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an implementation error within the SSL/TLS session handling process that can prevent the release of a session handler under specific conditions. An attacker could exploit this vulnerability by sending crafted SSL/TLS traffic to an affected device, increasing the probability of session handler leaks. A successful exploit could allow the attacker to eventually deplete the available session handler pool, preventing new sessions from being established and causing a DoS condition.

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.903% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ssl-dos-kxG8mpUA

History

Aug 11, 2026 8:00 PM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Cisco secure Firewall Threat Defense
CPEs	cpe:2.3:a:cisco:firepower_threat_defense:7.0.0.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.0:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.1.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.2.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.2:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.3:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.4:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.0.5:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.1.0.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.1.0.2:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.1.0.3:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.1.0:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.2.0.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.2.0:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.2.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.2.2:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.2.3:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.3.0:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.3.1.1:::::::* cpe:2.3:a:cisco:firepower_threat_defense:7.3.1:::::::*	cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.0.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.0:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.1.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.2.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.2:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.3:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.4:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.0.5:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0.2:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0.3:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.1.0:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.0.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.0:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.2:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.2.3:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.3.0:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.3.1.1:::::::* cpe:2.3:a:cisco:secure_firewall_threat_defense:7.3.1:::::::*
Vendors & Products	Cisco firepower Threat Defense	Cisco secure Firewall Threat Defense