Cisco Secure ACS 3.x before 3.3(4) Build 12 patch 7, 4.0.x, 4.1.x before 4.1(4) Build 13 Patch 11, and 4.2.x before 4.2(0) Build 124 Patch 4 does not properly handle an EAP Response packet in which the value of the length field exceeds the actual packet length, which allows remote authenticated users to cause a denial of service (CSRadius and CSAuth service crash) or possibly execute arbitrary code via a crafted RADIUS (1) EAP-Response/Identity, (2) EAP-Response/MD5, or (3) EAP-Response/TLS Message Attribute packet.

Stack-based buffer overflow in the CSAdmin service in Cisco Secure Access Control Server (ACS) for Windows before 4.1 and ACS Solution Engine before 4.1 allows remote attackers to execute arbitrary code via a crafted HTTP GET request.

Stack-based buffer overflow in the CSRadius service in Cisco Secure Access Control Server (ACS) for Windows before 4.1 and ACS Solution Engine before 4.1 allows remote attackers to execute arbitrary code via a crafted RADIUS Accounting-Request packet.

Multiple unspecified vulnerabilities in the CSRadius service in Cisco Secure Access Control Server (ACS) for Windows before 4.1 and ACS Solution Engine before 4.1 allow remote attackers to cause a denial of service (crash) via a crafted RADIUS Access-Request packet. NOTE: it has been reported that at least one issue is a heap-based buffer overflow involving the Tunnel-Password attribute.

Cisco Secure Access Control Server (ACS) 4.x for Windows uses the client's IP address and the server's port number to grant access to an HTTP server port for an administration session, which allows remote attackers to bypass authentication via various methods, aka "ACS Weak Session Management Vulnerability."

Cross-site scripting (XSS) vulnerability in LogonProxy.cgi in Cisco Secure ACS for UNIX 2.3 allows remote attackers to inject arbitrary web script or HTML via the (1) error, (2) SSL, and (3) Ok parameters.

Cisco Secure Access Control Server (ACS) 3.x for Windows stores ACS administrator passwords and the master key in the registry with insecure permissions, which allows local users and remote administrators to decrypt the passwords by using Microsoft's cryptographic API functions to obtain the plaintext version of the master key.

The Downloadable RADIUS ACLs feature in Cisco PIX and VPN 3000 concentrators, when creating an ACL on the Cisco Secure Access Control Server (CS ACS), generates a random internal name for an ACL that is also used as a hidden user name and password, which allows remote attackers to gain privileges by sniffing the username from the cleartext portion of a RADIUS session, then using the password to log in to another device that uses CS ACS.

Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later packets because they appear to be too old.

Cisco Secure Access Control Server for Windows (ACS Windows) and Cisco Secure Access Control Server Solution Engine (ACS Solution Engine) 3.3.1, when the EAP-TLS protocol is enabled, does not properly handle expired or untrusted certificates, which allows remote attackers to bypass authentication and gain unauthorized access via a "cryptographically correct" certificate with valid fields such as the username.