Anyconnect Secure Mobility ClientApplication · Cisco
CVE-2021-1429
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 · uneditedMultiple vulnerabilities in the install, uninstall, and upgrade processes of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to hijack DLL or executable files that are used by the application. A successful exploit could allow the attacker to execute arbitrary code on an affected device with SYSTEM privileges. To exploit these vulnerabilities, the attacker must have valid credentials on the Windows system. For more information about these vulnerabilities, see the Details section of this advisory.
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 confidenceThis vulnerability in Cisco AnyConnect for Windows allows an authenticated local attacker to hijack DLL or executable files during the install, uninstall, or upgrade processes. By planting malicious DLLs or executables in locations where the application loads them, an attacker can achieve arbitrary code execution with SYSTEM-level privileges.
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
< 4.10.00093CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Verify Cisco AnyConnect is installedOpen Control Panel > Programs and Features, or run 'Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "*AnyConnect*"}' in PowerShell to list installed AnyConnect packagesAffected if Any Cisco AnyConnect Secure Mobility Client entry appears in installed programs
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Determine the installed version numberIn Programs and Features, click on Cisco AnyConnect Secure Mobility Client and view the Version column, or run 'Get-ItemProperty "C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\vpnui.exe" | Select-Object VersionInfo' in PowerShellAffected if The version shown is lower than 4.10.00093 (for example, 4.9.x, 4.8.x, etc.)
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Confirm the vulnerable component existsCheck if the AnyConnect installation directory exists at 'C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\' and contains the main executable files such as vpnui.exe, vpn.exe, or core.exeAffected if The directory and executables exist, indicating a full installation rather than a minimal or per-user install
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Identify DLL load points during maintenance operationsReview the AnyConnect installation directory for writable subfolders where the application loads DLLs during install, uninstall, or upgrade. Common locations include the main folder and any module subfolders under the installation pathAffected if The installation directory or its subfolders are writable by non-privileged users, allowing DLL planting
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Check for existing unauthorized DLLs or executablesUse File Explorer or PowerShell to list all .dll and .exe files in the AnyConnect installation folder that were not part of the original package, looking for recently added or unexpected filesAffected if Unexpected DLL or executable files are present in the AnyConnect installation directory
A system is affected if Cisco AnyConnect Secure Mobility Client is installed with a version lower than 4.10.00093 and the installation directory is accessible for DLL/executable hijacking during maintenance operations.
Generated from the published advisory. Verify against your own configuration.
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 data4.10.00093
Apply the vendor patch from Cisco for AnyConnect Secure Mobility Client. Restrict local access to trusted users only and monitor for unauthorized DLLs or executables in AnyConnect installation directories.
Fix this in Anyconnect Secure Mobility Client
Scoped from the published advisory
- Consultation3.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1429 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-1429 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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