CVE-2021-1567
Cisco AnyConnect Secure Mobility Client for Windows with VPN Posture (HostScan) Module DLL Hijacking Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.0
Cisco AnyConnect Secure Mobility Client for Windows with VPN Posture (HostScan) Module DLL Hijacking Vulnerability
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.
- Record
CVE-2021-1567- CVSS 3.1
- 7.0 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-367
- Updated
- 2026-11-02
EUVDEUVD-2021-7034
7.0
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.
- Record
EUVD-2021-7034- CVSS 3.1
- 7.0 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-wxfr-9v84-73vc
6.7
A vulnerability in the DLL loading mechanism of Cisco AnyConnect Secure Mobility Client for...
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.
- Record
GHSA-wxfr-9v84-73vc- CVSS 3.1
- 6.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-367, CWE-427
- Updated
- 2026-11-02
NVD
7.0
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.
- Record
CVE-2021-1567- CVSS 3.1
- 7.0 High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - CVSS 3.1
- 6.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.2 Medium
AV:L/AC:H/Au:N/C:C/I:C/A:C - Weakness
- CWE-367, CWE-427
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-1567 is a high vulnerability (CVSS 7.0) in Cisco Anyconnect Secure Mobility Client, published June 16, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.18%, the 7th percentile. No source names a fixed version.