CVE-2016-4711
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 · uneditedCCrypt in corecrypto in CommonCrypto in Apple iOS before 10 and OS X before 10.12 allows attackers to discover cleartext information by leveraging a function call that specifies the same buffer for input and output.
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 confidenceThe vulnerability exists in CCrypt within corecrypto/CommonCrypto on Apple iOS before version 10 and OS X before 10.12. The flaw involves cryptographic functions that allow specifying the same memory buffer for both input and output parameters, which can leak cleartext information during encryption/decryption operations.
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<= 9.3.5<= 10.11.6CVSS 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
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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 iOS version on Apple mobile devicesOn the iOS device, navigate to Settings > General > About > Version to view the installed iOS version numberAffected if The displayed version is 9.3.5 or lower (any version up to and including 9.3.5)
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Check macOS version on Apple computersOn the Mac, click the Apple menu in the top-left corner and select About This Mac to view the installed macOS versionAffected if The displayed version is 10.11.6 or lower (any version up to and including 10.11.6)
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Identify the CommonCrypto library versionFor developers: inspect the corecrypto framework binary or check system libraries at /System/Library/Frameworks/corecrypto.framework for version informationAffected if The framework is from an iOS version 9.x or lower, or macOS version 10.11.x or lower
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Review code using CCrypt or CommonCrypto encryption functionsSearch application source code for calls to CCCrypt, CCCryptor, or similar CommonCrypto functions where the input and output buffers are passed as the same parameterAffected if The application code passes identical memory buffers for both input and output parameters in cryptographic operations
The environment is affected if the device runs iOS 9.3.5 or earlier, or macOS 10.11.6 or earlier, AND the CommonCrypto/ccrypt API is being called with the same buffer for both input and output parameters.
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 dataUpgrade affected devices to iOS 10 or later and macOS 10.12 or later to obtain the patched version of CommonCrypto.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-4711 — 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-2016-4711 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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- 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