Medium severity · published Dec 12, 2023
CVE-2023-20275
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…
4.3
CVSS
0.4%
EPSS
No
On KEV
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 authenticated, remote attacker to send packets with another VPN user's source IP address. This vulnerability is due to improper validation of the packet's inner source IP address after decryption. An attacker could exploit this vulnerability by sending crafted packets through the tunnel. A successful exploit could allow the attacker to send a packet impersonating another VPN user's IP address. It is not possible for the attacker to receive return packets.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AS
Adaptive Security Appliance Software · Cisco
9.8.1; 9.8.1.5; 9.8.1.7; 9.8.2; 9.8.2.8; 9.8.2.14; +34 more · source: NVD
SF
Secure Firewall Threat Defense · Cisco
6.2.3; 6.2.3.1; 6.2.3.2; 6.2.3.3; 6.2.3.4; 6.2.3.5; +34 more · source: NVD
Affected product
AS
Adaptive Security Appliance Software
Cisco
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-20275
CVE.org
https://www.cve.org/CVERecord?id=CVE-2023-20275
Vendor Advisory
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-vpn-Y88QOm77
More from Adaptive Security Appliance Software
9.9
CVE-2025-20333
Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability
9.1
CVE-2023-20269
Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability
8.8
CVE-2016-6366
Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow Vulnerability
8.6
CVE-2026-20349
Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software Remote Access SSL VPN Denial of Service Vulnerability
8.6
CVE-2025-20362
Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Missing Authorization Vulnerability