CVE-2021-34788: Cisco AnyConnect Secure Mobility Client for Linux and Mac OS with VPN Posture (HostScan) Module Shared Library Hijacking Vulnerability

Severity: high (CVSS 7.0 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: 2021-10-06 · updated 2026-06-17
Weakness: CWE-367

Description

A vulnerability in the shared library loading mechanism of Cisco AnyConnect Secure Mobility Client for Linux and Mac OS could allow an authenticated, local attacker to perform a shared library 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 shared library 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 root privileges. To exploit this vulnerability, the attacker must have a valid account on the system.

Affected products

Cisco AnyConnect Secure Mobility Client: before 4.10.03104 — fixed in 4.10.03104

How to fix

Upgrade to a fixed version: Cisco AnyConnect Secure Mobility Client 4.10.03104. Check the vendor advisory for mitigations.

References

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