dbcve.org
Anyconnect Secure Mobility ClientApplication · Cisco

CVE-2021-1568

MEDIUM · 5.5 CVSS v3.1 Published 2021-06-16
Fix available
A fix is available. Upgrade to 4.10.01075 or later.
See remediation →
57/100
Remediation priority · Elevated
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 Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected system. This vulnerability is due to uncontrolled memory allocation. An attacker could exploit this vulnerability by copying a crafted file to a specific folder on the system. A successful exploit could allow the attacker to crash the VPN Agent service when the affected application is launched, causing it to be unavailable to all users of the system. To exploit this vulnerability, the attacker must have valid credentials on a multiuser Windows system.

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 · moderate confidence

A vulnerability in Cisco AnyConnect Secure Mobility Client for Windows allows an authenticated local attacker to cause uncontrolled memory allocation by copying a crafted file to a specific folder on the system. When the affected application is launched, this causes the VPN Agent service to crash, rendering it unavailable to all users of the multiuser Windows system.

MitigationApply the vendor patch from Cisco for CVE-2021-1568. Until patched, restrict write access to the specific folder used in the attack and ensure strong authentication controls on affected systems.

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:< 4.10.01075

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
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 is installed
    Open Control Panel > Programs and Features, or run 'Get-ItemProperty HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\* | Select-Object DisplayName, DisplayVersion' in PowerShell to list installed programs
    Affected if Cisco AnyConnect Secure Mobility Client appears in the installed programs list
  2. Check the installed version number
    Run 'Get-ItemProperty "C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\vpndownloader.exe" -ErrorAction SilentlyContinue | Select-Object VersionInfo' or check the version via the GUI by right-clicking the AnyConnect icon and selecting 'About'
    Affected if The displayed version is lower than 4.10.01075 (for example, 4.9.x, 4.8.x, etc.)
  3. Verify the VPN Agent service exists
    Open Services (services.msc) and look for 'Cisco AnyConnect Secure Mobility Agent' or run 'Get-Service -Name *Cisco* -ErrorAction SilentlyContinue' in PowerShell
    Affected if The Cisco AnyConnect VPN Agent service is present on the system
  4. Check the specific folder used in the attack
    Identify the target folder by reviewing AnyConnect configuration files in 'C:\ProgramData\Cisco\Cisco AnyConnect Secure Mobility Client\' or the user's AppData folder, as the CVE mentions a crafted file must be copied to a specific location
    Affected if Write permissions exist for standard users on the folder where AnyConnect stores runtime or configuration files
  5. Compare version against affected range
    Document the exact version number found in step 2 and compare it against the vulnerable range: any version before 4.10.01075
    Affected if The installed version is less than 4.10.01075

A system is affected if Cisco AnyConnect Secure Mobility Client for Windows is installed with a version lower than 4.10.01075 and the VPN Agent service is present.

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.

From vendor data
Upgrade available Upgrade to 4.10.01075 or later
Fixed in 4.10.01075
Interim mitigation

Apply the vendor patch from Cisco for CVE-2021-1568. Until patched, restrict write access to the specific folder used in the attack and ensure strong authentication controls on affected systems.

Fix this in Anyconnect Secure Mobility Client Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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Scan for this in your stack

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dbcve dependency scanner

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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-2021-1568 in production — separate from our analysis above.

No notes yet

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data