dbcve.org
BonjourApplication · Apple

CVE-2011-0220

MEDIUM · 5.5 CVSS v3.1 Published 2020-02-05
Fix available
A fix is available. Upgrade to 2011 or later.
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
Apple Bonjour before 2011 allows a crash via a crafted multicast DNS packet.

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

Apple Bonjour (mDNSResponder) before 2011 contains a vulnerability in its multicast DNS packet handling that allows a remote attacker to cause a denial of service via a crafted malicious mDNS packet.

MitigationUpdate Apple Bonjour/mDNSResponder to a version released after 2011, or apply the relevant Apple security update.

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
BonjourApplication
Affected:< 2011

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. Verify mDNSResponder service is running
    On macOS: ps aux | grep mDNSResponder. On Windows: check Services for 'Bonjour Service' or 'mDNSResponder'
    Affected if mDNSResponder process is active and running on the system
  2. Determine mDNSResponder version
    On macOS: /usr/sbin/mDNSResponder -version or ls -la /usr/sbin/mDNSResponder. On Windows: right-click the Bonjour service exe in Program Files and check Properties > Details for version info
    Affected if Version date is earlier than 2011 or version string indicates pre-2011 release
  3. Check Bonjour installation date
    On macOS: ls -la /usr/sbin/mDNSResponder or check System Information > Software > Installations. On Windows: check file properties of mDNSResponder.exe in Program Files
    Affected if Installation or binary creation date is before 2011
  4. Verify mDNS multicast listening is enabled
    Check if port 5353/udp is open and listening: sudo lsof -i :5353 -P -n on macOS, or netstat -an | findstr 5353 on Windows
    Affected if mDNSResponder is actively listening on multicast address 224.0.0.251 port 5353

The system is affected if mDNSResponder/Bonjour is running and its version or installation date predates 2011, exposing the multicast DNS service to the denial-of-service 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
Upgrade available Upgrade to 2011 or later
Fixed in 2011
Interim mitigation

Update Apple Bonjour/mDNSResponder to a version released after 2011, or apply the relevant Apple security update.

Fix this in Bonjour Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.

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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-2011-0220 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