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Anyconnect Secure Mobility ClientApplication · Cisco

CVE-2021-1450

MEDIUM · 5.5 CVSS v3.1 Published 2021-02-24
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 the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client 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 device. The vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending one or more crafted IPC messages 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. Note: The process under attack will automatically restart so no action is needed by the user or admin.

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

The vulnerability exists in the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client. An authenticated local attacker with valid credentials can send crafted IPC messages containing insufficiently validated user-supplied input to the AnyConnect process, causing it to crash and result in a denial of service condition. While the process automatically restarts, the DoS interruption still occurs.

MitigationApply the vendor patch from Cisco when available; until then, limit system access to trusted authenticated users only and monitor for suspicious IPC message activity targeting the AnyConnect process.

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:= 4.9\(5086\)

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:3.1/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify AnyConnect installation and version
    Locate the Cisco AnyConnect client on the system and determine its exact version number. On Windows, this is typically found in Add/Remove Programs, or by checking the program's properties. On macOS, check /Applications for Cisco AnyConnect. The specific vulnerable version is 4.9 build 5086.
    Affected if The installed version is exactly 4.9 (5086)
  2. Confirm the vulnerable version matches
    Verify that the build number matches 5086 specifically. Compare your installed AnyConnect version string against '4.9(5086)' as shown in the affected products list.
    Affected if The version string equals 4.9(5086)
  3. Assess local authentication exposure
    Determine if the system permits local user accounts or has users with valid credentials who can log in locally. Since this vulnerability requires an authenticated local attacker, check for local user accounts, shared credentials, or systems where multiple users have login access.
    Affected if Local authenticated users or shared credential accounts exist on the system
  4. Check for AnyConnect process crash indicators
    Review system logs, application event logs (Windows Event Viewer), or AnyConnect-specific logs for evidence of the vpnui.exe or acvpui.exe processes crashing unexpectedly. Look for sudden process termination events occurring with the AnyConnect client.
    Affected if AnyConnect process crash events are logged or the client becomes intermittently unavailable

You are affected if Cisco AnyConnect version 4.9 build 5086 is installed and the system allows local authenticated access, which would enable an attacker to send malicious IPC messages causing denial of service.

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 vendor patch from Cisco when available; until then, limit system access to trusted authenticated users only and monitor for suspicious IPC message activity targeting the AnyConnect process.

Fix this in Anyconnect Secure Mobility Client Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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Scan for this in your stack

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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-2021-1450 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