← WebKit Silent-Fix Report — 2026-W34

7d09127ca947791dc0a72109466a9b0433ab898e  Return a digest instead of the Cookie header for Vary: Cookie validation

severity medium class CrossOrigin confidence 0.55 CookieJar / Vary:Cookie validation
Zak Ridouh Tue Aug 18 12:48:54 2026 -0700 full: 7d09127ca947791dc0a72109466a9b0433ab898e bug report ↗ view on GitHub ↗
Primitive: Send cookie digest instead of raw Cookie header to web process for Vary validation
Triage note: Adds cookieRequestHeaderFieldValueDigest returning a SHA1 digest so WebKit2 can compare header values 'without sending the header to a web process', closing a cross-process cookie disclosure to the untrusted content process.

Security-relevant, below the exploitable-grade bar for a full root-cause writeup. The triage verdict is above; the side-by-side patch is below.

Before / after

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