Anyconnect Secure Mobility ClientApplication · Cisco
CVE-2020-3434
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 · uneditedA vulnerability in the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device. To exploit this vulnerability, the attacker would need to have valid credentials on the Windows system. The vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a crafted IPC message to the AnyConnect process on an affected device. A successful exploit could allow the attacker to stop the AnyConnect process, causing a DoS condition on the device. To exploit this vulnerability, the attacker would need to have valid credentials on the 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 · high confidenceA vulnerability exists in the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client for Windows. An authenticated local attacker with valid Windows credentials can send a crafted IPC message to the AnyConnect process. Due to insufficient validation of user-supplied input, the message causes the AnyConnect process to terminate, resulting in a denial of service condition.
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
<= 4.9.00086CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check if Cisco AnyConnect is installed on WindowsOpen Programs and Features (appwiz.cpl) or check for the AnyConnect client in the system. Look for 'Cisco AnyConnect Secure Mobility Client' in the installed programs list.Affected if Cisco AnyConnect Secure Mobility Client for Windows is present on the system
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Find the installed version of Cisco AnyConnectOpen Programs and Features, locate 'Cisco AnyConnect Secure Mobility Client', and note the version shown in the 'Version' column. Alternatively, check the file version of the main executable (typically at C:\Program Files\Cisco\Cisco AnyConnect Secure Mobility Client\vpndownload.exe or vpnui.exe) by right-clicking and viewing Properties > Details.Affected if The version displayed is 4.9.00086 or any earlier version number (versions 4.9.x through 4.9.00086 are all affected)
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Confirm the specific version string matches affected rangeCompare the installed version to the affected range. AnyConnect versions are typically displayed in format like '4.9.00086' or '4.9.x'. Check if the full version string is exactly 4.9.00086 or numerically less (earlier).Affected if The installed version is 4.9.00086 or any version numerically lower (e.g., 4.9.00085, 4.8.x, 4.7.x, etc.)
The system is affected if Cisco AnyConnect Secure Mobility Client for Windows is installed and the installed version is 4.9.00086 or any earlier version.
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 dataApply the vendor security patch from Cisco for CVE-2020-3434. Until patched, limit local access to trusted users only, as the attacker requires valid Windows credentials.
Fix this in Anyconnect Secure Mobility Client
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3434 — 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-2020-3434 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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