CVE-2021-1519: 
Cisco AnyConnect Secure Client vulnerability analysis and mitigation

A vulnerability (CVE-2021-1519) was discovered in the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client Software. The vulnerability was first published on May 5, 2021, and affects Cisco AnyConnect Secure Mobility Client for Windows, MacOS, and Linux releases earlier than Release 4.10.00093. The vulnerability stems from insufficient validation of user-supplied input, which could allow an authenticated, local attacker to overwrite VPN profiles on an affected device (Cisco Advisory).

The vulnerability is tracked as CWE-20 (Improper Input Validation) and has received varying CVSS scores: NIST assigned a CVSS v3.1 Base Score of 5.5 (Medium) with vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N, while Cisco Systems assessed it at 4.7 (Medium) with vector CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N. The CVSS v2.0 score is 2.1 (Low) (NVD, Cisco Advisory).

A successful exploitation of this vulnerability allows an attacker to modify VPN profile files on the affected device. The attacker must have valid credentials on the affected system to exploit this vulnerability (Cisco Advisory).

Cisco has released software updates that address this vulnerability in AnyConnect Secure Mobility Client version 4.10.00093 and later. No workarounds are available for this vulnerability. The fix is available for Windows, MacOS, and Linux platforms (Cisco Advisory).

The vulnerability was reported by Gerbert Roitburd of Secure Mobile Networking Lab (TU Darmstadt) (Cisco Advisory).