Anyconnect Secure Mobility ClientApplication · Cisco
CVE-2021-1428
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 · moderate confidenceMultiple DLL and executable hijacking vulnerabilities exist in Cisco AnyConnect's install, uninstall, and upgrade processes on Windows. An authenticated local attacker with valid Windows credentials can place malicious DLLs or executables in locations where the installer searches, achieving arbitrary code execution with SYSTEM 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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Check Cisco AnyConnect installed versionOpen Windows Programs and Features, locate 'Cisco AnyConnect Secure Mobility Client', and note the version number; alternatively, right-click the AnyConnect executable (typically in C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\) and select Properties > Details to view the File VersionAffected if The installed version is lower than 4.10.00093 (for example, 4.9.x, 4.8.x, or earlier)
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Verify installation directory permissionsRight-click the Cisco AnyConnect installation folder (commonly C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\), select Properties > Security, and examine which users or groups have Write or Modify permissionsAffected if Non-privileged users or the Users group have Write or Modify access to the installation directory
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Check for unauthorized DLLs or executables in installation foldersOpen the AnyConnect installation directory and inspect all .dll and .exe files for unexpected or recently added files that do not match standard Cisco componentsAffected if Suspicious DLLs or executables are present that were not shipped with the official installer
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Review Windows Event Logs for installer activityOpen Event Viewer, navigate to Windows Logs > Application and System, and filter for installation events from MSIInstaller or Cisco-related sources, noting any entries initiated by non-administrator accountsAffected if Installation or modification events were triggered by low-privilege user accounts
A system is likely affected if the installed AnyConnect version is below 4.10.00093 AND the installation directory permits write access to non-privileged users, creating the condition for DLL/executable hijacking.
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 Cisco's security patches for AnyConnect when available, restrict local administrator access, and ensure installation directories are protected against write access by non-privileged users.
Fix this in Anyconnect Secure Mobility Client
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 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 $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1428 — 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-2021-1428 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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