CVE-2020-3556

What it is

A vulnerability in the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client Software could allow an authenticated, local attacker to cause a targeted AnyConnect user to execute a malicious script. The vulnerability is due to a lack of authentication to the IPC listener. An attacker could exploit this vulnerability by sending crafted IPC messages to the AnyConnect client IPC listener. A successful exploit could allow an attacker to cause the targeted AnyConnect user to execute a script. This script would execute with the privileges of the targeted AnyConnect user. In order to successfully exploit this vulnerability, there must be an ongoing AnyConnect session by the targeted user at the time of the attack. To exploit this vulnerability, the attacker would also need valid user credentials on the system upon which the AnyConnect client is being run. Cisco has not released software updates that address this vulnerability.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account, but needs a user to act. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2020-11-06 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:18 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 7.3 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2020-11-06 19:15 UTC

Last modified

2026-06-17 03:18 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Cisco Anyconnect Secure Mobility Client 4.9\(3052\)
• Cisco Anyconnect Secure Mobility Client 98.145\(86\)

Attack profile CVSS 3.1 · 7.3

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2020-3556.md and follow it. Check whether this project is affected by CVE-2020-3556. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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