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Anyconnect Secure Mobility ClientApplication · Cisco

CVE-2021-40124

HIGH · 7.8 CVSS v3.1 Published 2021-11-04
Fix available
A fix is available. Upgrade to 4.10.03104 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the Network Access Manager (NAM) module of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to escalate privileges on an affected device. This vulnerability is due to incorrect privilege assignment to scripts executed before user logon. An attacker could exploit this vulnerability by configuring a script to be executed before logon. A successful exploit could allow the attacker to execute arbitrary code with SYSTEM privileges.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a privilege escalation vulnerability in Cisco AnyConnect Secure Mobility Client's Network Access Manager (NAM) module for Windows. Scripts configured to execute before user logon run with SYSTEM privileges instead of properly restricted privileges. An authenticated local attacker can configure a malicious script to execute pre-logon and achieve arbitrary code execution with SYSTEM-level privileges.

MitigationApply vendor patches when available; restrict local administrative access to prevent attackers from modifying NAM script configurations; audit existing pre-logon script configurations for unauthorized changes.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Anyconnect Secure Mobility ClientApplication
Affected:< 4.10.03104

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Cisco AnyConnect installation and version
    Check the installed version by querying the Windows Registry key: HKLM\SOFTWARE\Cisco\AnyConnect\CurrentVersion, or examine the file version of 'AnyConnect.exe' in the program files directory (commonly C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\).
    Affected if The installed version is less than 4.10.03104.
  2. Confirm Network Access Manager module is present
    Check if the NAM module is installed by looking for the presence of the 'NAM' directory under the Cisco AnyConnect installation path, or check the Windows service named 'Cisco AnyConnect NAM Service' (service display name typically contains 'Network Access Manager').
    Affected if The NAM module is installed and the service exists.
  3. Identify configured pre-logon scripts
    Examine the NAM configuration for pre-logon scripts. Check the Windows Registry under HKLM\SOFTWARE\Cisco\AnyConnect\NAM\Profiles for script configurations, or locate the NAM profile XML files in the installation directory (commonly in C:\ProgramData\Cisco\Cisco AnyConnect Secure Mobility Client\NAM\).
    Affected if Any pre-logon or pre-authentication scripts are configured in NAM.
  4. Verify script execution context
    Review the configured NAM scripts to confirm they are set to execute before user logon. Check the script configuration files or registry entries for 'PreLogon' or 'PreAuth' execution flags.
    Affected if Scripts are configured with pre-logon execution enabled and the Cisco AnyConnect version is below 4.10.03104.

A user is affected if Cisco AnyConnect with the NAM module is installed at a version below 4.10.03104 and has pre-logon scripts configured, allowing potential SYSTEM-level privilege escalation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.10.03104 or later
Fixed in 4.10.03104
Interim mitigation

Apply vendor patches when available; restrict local administrative access to prevent attackers from modifying NAM script configurations; audit existing pre-logon script configurations for unauthorized changes.

Recommended fix High confidence

4.10.03104 or later

  1. Check the current version of Cisco AnyConnect Secure Mobility Client installed on the system via Windows Programs and Features or the Add or Remove Programs dialog
  2. Download Cisco AnyConnect Secure Mobility Client version 4.10.03104 or later from Cisco's official software distribution (either Cisco Software Central or the Cisco AnyConnect Licensing portal)
  3. Install the updated Cisco AnyConnect Secure Mobility Client by running the installer with appropriate administrative privileges
  4. Verify the installed version matches the target fixed release after installation completes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Anyconnect Secure Mobility Client Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-40124 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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