CVE-2024-20355 Missing authorization in Cisco Adaptive Security Appliance (ASA) Software
Authenticated attackers can bypass VPN authorization checks to access unauthorized network segments by reusing SAML tokens across tunnel groups.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-20355?
CVE-2024-20355 is a medium-severity missing authorization vulnerability in Cisco Adaptive Security Appliance Software, published on 22 May 2024. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability in the implementation of SAML 2.0 single sign-on (SSO) for remote access VPN services in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to successfully establish a VPN session on an affected device. This vulnerability is due to improper separation of authorization domains when using SAML authentication. An attacker could exploit this vulnerability by using valid credentials to successfully authenticate using their designated connection profile (tunnel group), intercepting the SAML SSO token that is sent back from the Cisco ASA device, and then submitting the same SAML SSO token to a different tunnel group for authentication. A successful exploit could allow the attacker to establish a remote access VPN session using a connection profile that they are not authorized to use and connect to secured networks behind the affected device that they are not authorized to access. For successful exploitation, the attacker must have valid remote access VPN user credentials.
Weakness: CWE-862
Which versions are affected by CVE-2024-20355?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2024-20355?
No fix has been published for CVE-2024-20355 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2024-20355 being exploited?
There is no known exploitation of CVE-2024-20355 in the wild and no public exploit code.
Other vulnerabilities in Cisco Adaptive Security Appliance Software
- CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow
- CVE-2016-6366 Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow
- CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection
- CVE-2024-20353 Cisco ASA and FTD Denial of Service
- CVE-2016-6367 Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution
All Cisco Adaptive Security Appliance Software vulnerabilities
Sources
Also known as GHSA-2fpj-x8pr-gx6p.