Anyconnect Secure Mobility ClientApplication · Cisco
CVE-2021-1427
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 vulnerabilities in the install, uninstall, and upgrade processes of Cisco AnyConnect Secure Mobility Client for Windows allow an authenticated local attacker to hijack DLL or executable files used by the application. This enables arbitrary code execution with SYSTEM privileges by placing malicious DLLs or executables in locations where the application searches for these files during those processes.
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
< 4.9.06037CVSS 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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Locate Cisco AnyConnect installation on WindowsCheck if Cisco AnyConnect Secure Mobility Client is installed by looking in the default installation path (typically C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\) or by searching for the program in Windows Programs and Features.Affected if AnyConnect is installed on the system
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Determine the installed version of Cisco AnyConnectOpen the Cisco AnyConnect Secure Mobility Client application window and look for the version information typically displayed in the About or Help section, or check the program's properties by right-clicking the executable in Program Files. Alternatively, use PowerShell: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*' | Where-Object {$_.DisplayName -like '*AnyConnect*'} | Select-Object DisplayName, DisplayVersionAffected if A version number is found in the results
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Compare installed version against the vulnerable rangeCompare the discovered version number to 4.9.06037. Note that versions before this release (such as 4.8.x, 4.7.x, and earlier 4.9.x releases) are affected by this vulnerability.Affected if The installed version is lower than 4.9.06037 (for example, 4.9.05042, 4.8.01090, etc.)
A system is affected if Cisco AnyConnect Secure Mobility Client for Windows is installed with a version number lower than 4.9.06037.
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 data4.9.06037
Apply the vendor-provided security updates from Cisco for AnyConnect Secure Mobility Client. Ensure install, uninstall, and upgrade processes run from trusted, integrity-protected paths and verify the digital signatures of DLLs and executables loaded by the application.
Fix this in Anyconnect Secure Mobility Client
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1427 — 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-2021-1427 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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- 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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