dbcve.org
Anyconnect Secure Mobility ClientApplication · Cisco

CVE-2018-0373

MEDIUM · 5.5 CVSS v3.0 Published 2018-06-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 vpnva-6.sys for 32-bit Windows and vpnva64-6.sys for 64-bit Windows of Cisco AnyConnect Secure Mobility Client for Windows Desktop could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected system. The vulnerability is due to improper validation of user-supplied data. An attacker could exploit this vulnerability by sending a malicious request to the application. A successful exploit could allow the attacker to cause a DoS condition on the affected system. Cisco Bug IDs: CSCvj47654.

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 the Cisco AnyConnect VPN client kernel drivers (vpnva-6.sys for 32-bit and vpnva64-6.sys for 64-bit Windows) allows an authenticated local attacker to send malicious requests due to improper validation of user-supplied data, causing a denial of service condition on the affected system.

MitigationApply the Cisco security update for AnyConnect Secure Mobility Client. Until patched, limit local system access to trusted, authenticated users only.

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:= 4.5\(58\)= 4.5\(1044\)= 4.5\(2033\)= 4.5\(2036\)= 4.5\(3040\)= 4.5\(4029\)= 4.5\(5030\)= 4.6\(362\)= 4.6\(1098\)

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:3.0/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. Check if Cisco AnyConnect is installed
    Open Programs and Features or check for the presence of Cisco AnyConnect in the program directory (typically C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client)
    Affected if Cisco AnyConnect is not installed on the system
  2. Identify the installed AnyConnect version
    Check the version displayed in Programs and Features, or run 'vpncli.exe -version' from the AnyConnect installation directory, or check the registry key HKLM\SOFTWARE\Cisco\Cisco AnyConnect Secure Mobility Client\ClientVersion
    Affected if The version matches one of the following: 4.5.00058, 4.5.01044, 4.5.02033, 4.5.02036, 4.5.03040, 4.5.04029, 4.5.05030, 4.6.0362, 4.6.01098
  3. Verify presence of vulnerable kernel drivers
    Check for the existence of vpnva-6.sys (32-bit) or vpnva64-6.sys (64-bit) in the Windows system drivers directory (C:\Windows\System32\drivers\)
    Affected if Either driver file is present on the system
  4. Confirm the driver version is affected
    Right-click on the driver file, select Properties, and check the File Version attribute, or use PowerShell: Get-ItemProperty C:\Windows\System32\drivers\vpnva*.sys | Select-Object Name, Version
    Affected if The driver version matches the affected AnyConnect version numbers listed above

The system is affected if Cisco AnyConnect Secure Mobility Client is installed with any of the listed affected versions (4.5.00058 through 4.6.01098) and the corresponding vulnerable kernel driver (vpnva-6.sys or vpnva64-6.sys) 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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco security update for AnyConnect Secure Mobility Client. Until patched, limit local system access to trusted, authenticated users only.

Fix this in Anyconnect Secure Mobility Client Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA3.0 h
20.0 hours of engineering $3,420
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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-2018-0373 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