What’s Vulnerable › Vulnerabilities

CVE-2021-1567: Cisco AnyConnect Secure Mobility Client for Windows with VPN Posture (HostScan) Module DLL Hijacking Vulnerability

• Severity: medium (CVSS 6.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-16 · updated 2026-06-17
• Weakness: CWE-367

Description

A vulnerability in the DLL loading mechanism of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to perform a DLL hijacking attack on an affected device if the VPN Posture (HostScan) Module is installed on the AnyConnect client. This vulnerability is due to a race condition in the signature verification process for DLL files that are loaded on an affected device. An attacker could exploit this vulnerability by sending a series of crafted interprocess communication (IPC) messages to the AnyConnect process. A successful exploit could allow the attacker to execute arbitrary code on the affected device with SYSTEM privileges. To exploit this vulnerability, the attacker must have valid credentials on the Windows system.

Affected products

• Cisco AnyConnect Secure Mobility Client: before 4.10.01075 — fixed in 4.10.01075

How to fix

Upgrade to a fixed version: Cisco AnyConnect Secure Mobility Client 4.10.01075. Check the vendor advisory for mitigations.

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-pos-dll-ff8j6dFv
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-pos-dll-ff8j6dFv

Get alerted when CVE-2021-1567 or the next vulnerability affects your stack