dbcve.org
SafariWeb browser · Apple

CVE-2016-10226

HIGH · 7.5 CVSS v3.0 Published 2017-04-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
JavaScriptCore in WebKit, as distributed in Safari Technology Preview Release 18, allows remote attackers to cause a denial of service (bitfield out-of-bounds read and application crash) via crafted JavaScript code that is mishandled in the operatorString function, related to assembler/MacroAssemblerARM64.h, assembler/MacroAssemblerX86Common.h, and wasm/WasmB3IRGenerator.cpp.

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

A bitfield out-of-bounds read vulnerability exists in JavaScriptCore's operatorString function within WebKit (Safari Technology Preview Release 18). Crafted JavaScript code triggers the vulnerability in the macro assembler components (MacroAssemblerARM64.h, MacroAssemblerX86Common.h) and WebAssembly generator (WasmB3IRGenerator.cpp), causing a denial of service via application crash.

MitigationApply the vendor-supplied patch/update to Safari/WebKit. Until patched, users should avoid visiting untrusted or unknown websites to prevent malicious JavaScript from triggering the crash.

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:= 18

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
High

CVSS:3.0/AV:N/AC:L/PR:N/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. Check installed Safari version
    Open Safari > About Safari (or Safari > Settings > General on newer versions) and note the version number displayed. Alternatively, run 'defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionString' in Terminal.
    Affected if The version is exactly 18.0 (Safari Technology Preview Release 18)
  2. Confirm JavaScript is enabled
    Go to Safari > Settings > Security and verify 'Enable JavaScript' is checked. In Terminal, run: 'defaults read /Users/$USER/Library/Preferences/com.apple.Safari WebKitJavaScriptEnabled'
    Affected if JavaScript is enabled - this is required for the malicious crafted JavaScript to execute and trigger the vulnerability
  3. Verify WebAssembly support status
    In Safari, open the Develop menu > Experimental Features > check if WebAssembly is enabled. WebAssembly is typically enabled by default in affected versions.
    Affected if WebAssembly is enabled - the vulnerability exists in the WebAssembly generator (WasmB3IRGenerator.cpp) component
  4. Identify the specific WebKit component
    The affected code resides in JavaScriptCore's operatorString function within MacroAssemblerARM64.h, MacroAssemblerX86Common.h, and WasmB3IRGenerator.cpp. These are part of the WebKit engine bundled with Safari.
    Affected if Running Safari 18.0 with the bundled WebKit version containing the vulnerable macro assembler code

You are affected if you are running Safari Technology Preview Release 18.0 (exact version match) with JavaScript enabled, as the vulnerability is triggered through crafted JavaScript code executing in the JavaScriptCore engine.

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-supplied patch/update to Safari/WebKit. Until patched, users should avoid visiting untrusted or unknown websites to prevent malicious JavaScript from triggering the crash.

Fix this in Safari Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,360
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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-2016-10226 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