dbcve.org
UmbrellaApplication · Cisco

CVE-2021-1350

MEDIUM · 5.3 CVSS v3.1 Published 2021-01-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges 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 web UI of Cisco Umbrella could allow an unauthenticated, remote attacker to negatively affect the performance of this service. The vulnerability exists due to insufficient rate limiting controls in the web UI. An attacker could exploit this vulnerability by sending crafted HTTPS packets at a high and sustained rate. A successful exploit could allow the attacker to negatively affect the performance of the web UI. Cisco has addressed this vulnerability.

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 confidence

Insufficient rate limiting in Cisco Umbrella's web UI allows unauthenticated remote attackers to send crafted HTTPS packets at high sustained rates, degrading web UI performance. The vulnerability stems from missing or inadequate rate limiting controls in the UI component.

MitigationApply the vendor patch or update released by Cisco for this vulnerability to implement proper rate limiting controls in the Umbrella web UI.

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
UmbrellaApplication
Affected:all versions

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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. Access Cisco Umbrella dashboard and test responsiveness
    Log into your Cisco Umbrella dashboard at https://dashboard.umbrella.com or your custom org domain. Attempt to navigate between different sections (Reporting, Policies, API). Note any delays, timeouts, or failure to load pages.
    Affected if The dashboard consistently shows slow load times, timeouts, or unresponsiveness during normal usage periods.
  2. Check Cisco Umbrella service status
    Visit the Cisco Umbrella status page at https://status.umbrella.com or search for Cisco Umbrella status. Look for any posted incidents or performance advisories related to the web UI or dashboard.
    Affected if There is an active incident or advisory mentioning web UI degradation or rate limiting issues.
  3. Review authentication logs for high-volume requests
    If available, check Cisco Umbrella logging or your SIEM for authentication events to the umbrella dashboard. Look for patterns of many rapid requests from any single source IP.
    Affected if You observe sustained high-volume HTTPS requests to Umbrella UI endpoints that correlate with performance degradation.
  4. Confirm Umbrella subscription is active
    Verify your organization has an active Cisco Umbrella subscription and the web UI is in use. Check your account or billing for active Umbrella licenses.
    Affected if Your organization uses Cisco Umbrella and the web UI is accessible, since all versions are affected.

If you are a Cisco Umbrella customer using the web UI and experiencing unexplained dashboard slowness or unresponsiveness, especially during periods of normal usage, your environment may be affected by this rate limiting vulnerability.

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 or update released by Cisco for this vulnerability to implement proper rate limiting controls in the Umbrella web UI.

Fix this in Umbrella Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-1350 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-1350 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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