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SafariWeb browser · Apple

CVE-2011-3443

HIGH · 7.5 CVSS v2.0 Published 2012-03-02
Fix available
A fix is available. Upgrade to after 5.0.5 or later.
See remediation →
84/100
Remediation priority · High
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
Use-after-free vulnerability in WebKit, as used in Apple Safari before 5.0.6, allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption and application crash) via vectors related to improper list management for Cascading Style Sheets (CSS) @font-face rules.

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

Use-after-free vulnerability in WebKit's handling of CSS @font-face rules allows remote attackers to execute arbitrary code or cause heap memory corruption leading to application crash. The vulnerability stems from improper list management for @font-face rules.

MitigationUpdate Apple Safari to version 5.0.6 or later to patch the WebKit component. Alternatively, disable or restrict handling of custom web fonts until the update can be applied.

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
SafariWeb browser
Affected:<= 5.0.5= 1.0= 1.0.0= 1.0.0b1= 1.0.0b2= 1.0.1= 1.0.2= 1.0.3= 1.0b1= 1.1= 1.1.0= 1.1.1

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
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/A:P

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 installed Safari version
    Open Safari, go to Safari menu > About Safari (or press Cmd+,) to view the version number
    Affected if Version is 5.0.5 or lower, or matches any of these: 1.0, 1.0.0, 1.0.0b1, 1.0.0b2, 1.0.1, 1.0.2, 1.0.3, 1.0b1, 1.1, 1.1.0, 1.1.1
  2. Confirm WebKit framework presence
    On macOS, check /System/Library/Frameworks/WebKit.framework/Versions/Current or use 'defaults read /Applications/Safari.app/Contents/Info CFBundleVersion' to confirm WebKit is loaded
    Affected if WebKit framework exists and the Safari version falls within the affected ranges listed above
  3. Verify @font-face CSS rule handling is active
    Open Safari Preferences > Security and confirm 'Allow web fonts' is enabled (this is the default setting)
    Affected if Web fonts are enabled, which is required for the vulnerable @font-face code path to execute

You are affected if Safari version is 5.0.5 or lower, or matches any of the older version numbers (1.0 through 1.1.1), and web fonts/@font-face support is enabled in the browser settings.

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 a release after 5.0.5
Interim mitigation

Update Apple Safari to version 5.0.6 or later to patch the WebKit component. Alternatively, disable or restrict handling of custom web fonts until the update can be applied.

Fix this in Safari 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.

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-2011-3443 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