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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 25 Dec 2023.
SafariWeb browser · Apple

CVE-2023-42917

HIGH · 8.8 CVSS v3.1 Published 2023-11-30
Fix available
A fix is available. Upgrade to 2.42.3 / 14.1.2 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Remotely reachable No privileges

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 memory corruption vulnerability was addressed with improved locking. This issue is fixed in iOS 17.1.2 and iPadOS 17.1.2, macOS Sonoma 14.1.2, Safari 17.1.2. Processing web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been exploited against versions of iOS before iOS 16.7.1.

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 memory corruption vulnerability in WebKit (Apple's browser engine) that could be triggered by processing malicious web content, potentially leading to arbitrary code execution. The fix involved improved locking, indicating a race condition in memory management. This was actively exploited in the wild against iOS versions prior to iOS 16.7.1.

MitigationUpdate all affected devices to the patched versions: iOS 17.1.2/iPadOS 17.1.2 or later, macOS Sonoma 14.1.2 or later, or Safari 17.1.2 or later. For devices unable to upgrade to iOS 17, apply iOS 16.7.1 which also contains the fix.

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:< 17.1.2
Debian LinuxOperating system
Affected:= 11.0= 12.0
FedoraOperating system
Affected:= 38= 39
IpadosOperating system
Affected:< 15.8.1>= 16.0, < 16.7.3>= 17.0, < 17.1.2
Iphone OsOperating system
Affected:< 15.8.1>= 16.0, < 16.7.3>= 17.0, < 17.1.2
macOSOperating system
Affected:>= 14.0, < 14.1.2
Webkitgtk\+Web browser
Affected:< 2.42.3

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 Safari version on macOS
    Open Safari, go to Safari > About Safari to view the version number
    Affected if Version is earlier than 17.1.2 on macOS 14 (Sonoma) or earlier
  2. Check iOS version on iPhone
    Go to Settings > General > About to view the iOS version
    Affected if Version is earlier than 15.8.1, OR between 16.0 and 16.7.3, OR between 17.0 and 17.1.2
  3. Check iPadOS version on iPad
    Go to Settings > General > About to view the iPadOS version
    Affected if Version is earlier than 15.8.1, OR between 16.0 and 16.7.3, OR between 17.0 and 17.1.2
  4. Check WebKitGTK version on Debian or Fedora Linux
    Run dpkg -l | grep webkit2gtk (Debian) or rpm -qa | grep webkit2gtk (Fedora) to list installed WebKit packages
    Affected if Version is earlier than 2.42.3 (such as 2.42.0, 2.40.x, or earlier)
  5. Verify WebView usage on affected platforms
    Confirm whether Safari, any app using UIWebView/WKWebView, or webkit2gtk-based browsers (like Epiphany) are actively used on the device
    Affected if The vulnerable WebKit component is actively used to render untrusted web content

You are affected if your Safari/iOS/iPadOS/macOS or WebKitGTK version falls within the affected ranges and you use WebKit to browse web content.

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.

dbcve · scoped
Upgrade available Upgrade to 2.42.3 / 14.1.2 / 15.8.1 or later
Fixed in 2.42.314.1.215.8.1
Interim mitigation

Update all affected devices to the patched versions: iOS 17.1.2/iPadOS 17.1.2 or later, macOS Sonoma 14.1.2 or later, or Safari 17.1.2 or later. For devices unable to upgrade to iOS 17, apply iOS 16.7.1 which also contains the fix.

Recommended fix High confidence

iOS 17.1.2 / iPadOS 17.1.2 / macOS Sonoma 14.1.2 / Safari 17.1.2

  1. Check current Safari version: Open Safari > Safari menu > About Safari
  2. Check current iOS/iPadOS version: Settings > General > About > Version
  3. Check current macOS version: Apple menu > About This Mac > Version
  4. For iOS/iPadOS: Go to Settings > General > Software Update and update to iOS/iPadOS 17.1.2 or later
  5. For macOS: Go to System Settings > General > Software Update and update to macOS Sonoma 14.1.2 or later
  6. For Safari (if standalone): Open App Store > Updates and update to Safari 17.1.2 or later
  7. After update, verify the fix by checking About Safari shows version 17.1.2 or higher
Caveat Standard iOS/macOS update; backup recommended before updating

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Safari Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

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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-2023-42917 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