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CVE-2016-9642 Webkit CVE debrief

CVE-2016-9642 describes a denial-of-service issue in WebKit’s JavaScriptCore engine caused by an out-of-bounds heap read. The issue is classified as CWE-125 and, per NVD, has a CVSS 3.0 score of 5.5 (MEDIUM) with availability impact only. The supplied CVSS vector indicates local access plus user interaction, which fits a scenario where a crafted JavaScript file is opened or otherwise processed by the affected component. For defenders, the main concern is service or application instability rather than data theft or code execution. Any product that embeds or depends on WebKit/JavaScriptCore and accepts untrusted JavaScript or web content should treat this as a crash-risk issue and verify it is on a vendor-fixed build.

Vendor
Webkit
Product
CVE-2016-9642
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2017-02-03
Original CVE updated
2026-05-13
Advisory published
2017-02-03
Advisory updated
2026-05-13

Who should care

Security teams responsible for browsers, embedded WebKit/JavaScriptCore integrations, desktop applications that render untrusted web content, and incident responders triaging crashes in affected WebKit-based software.

Technical summary

NVD identifies the affected product family as WebKit (CPE: cpe:2.3:a:webkit:webkit:-:*:*:*:*:*:*:*). The vulnerability is an out-of-bounds heap read in JavaScriptCore, mapped to CWE-125, and the published CVSS 3.0 vector is AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. That combination indicates an attacker needs user interaction and can reliably target availability, consistent with denial-of-service behavior from a crafted JavaScript input.

Defensive priority

Medium. Prioritize if you operate WebKit/JavaScriptCore in environments that process untrusted content, because crashes in a shared runtime can affect availability across multiple applications or services.

Recommended defensive actions

  • Check whether any deployed products embed WebKit or JavaScriptCore and compare them against the vendor’s security advisories for CVE-2016-9642.
  • Apply the maintainer’s patched release or security update that addresses this CVE when available through your normal software update process.
  • Treat unexpected WebKit/JavaScriptCore crashes, especially those triggered by JavaScript parsing or execution, as security-relevant and investigate for exposure to untrusted input.
  • Reduce exposure of WebKit-based components to untrusted JavaScript or content where practical, and prefer sandboxed or least-privilege deployment patterns.
  • Use the linked CVE/NVD record and third-party advisories as the authoritative starting points for verification and remediation tracking.

Evidence notes

The debrief is grounded in the supplied CVE/NVD metadata and linked references. NVD describes the issue as a WebKit JavaScriptCore out-of-bounds heap read with CVSS 3.0 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H and CWE-125. The reference set also includes an oss-security mailing-list thread dated 2016-11-26, plus SecurityFocus, SecurityTracker, and Gentoo GLSA entries. Timing context uses the CVE published date 2017-02-03 and modified date 2026-05-13 from the supplied record; no later generation or review time is treated as the vulnerability date.

Official resources

Public disclosure context in the supplied corpus starts with an oss-security reference dated 2016-11-26. The CVE/NVD record itself is published on 2017-02-03 and was last modified on 2026-05-13. This debrief uses the CVE published date for,