Bug 301688

Summary:

Web Inspector: Huge memory leak when devtools open

Product:

WebKit

Reporter:

Jozef <32jojo32>

Component:

Web Inspector

Assignee:

Nobody <webkit-unassigned>

Status:

NEW

Severity:

Critical

CC:

a_panta, ap, inspector-bugzilla-changes, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

All

OS:

All

Attachments:

Description	Flags
video evidence	none

Jozef

Reported 2025-10-30 05:13:22 PDT

Created attachment 477230 [details] video evidence Safari consumes 48GB+ of RAM when using `@csstools/css-tokenizer` to parse CSS. Issue occurs ONLY when DevTools is open. Page becomes unresponsive. Chrome/Firefox work fine. Environment Safari: Latest (macOS 26.0.1) — also tested with Safari 18 and 17; the same issue occurs there via BrowserStack. Extensions: No extensions enabled Reproduction Live Demo: https://safari-memory-leak.vercel.app Repository: https://github.com/Joozty/safari-memory-leak Quick Test (Live Demo) 1. Open https://safari-memory-leak.vercel.app in Safari 2. Open DevTools - Required to trigger the bug 3. Reload page 4. Memory spikes to 48GB+, page fails to reload Video Evidence - Normal window: https://github.com/Joozty/safari-memory-leak/raw/refs/heads/main/public/normal.mp4 - Incognito window: https://github.com/Joozty/safari-memory-leak/raw/refs/heads/main/public/incognito.mp4

Attachments
video evidence (1.96 MB, video/mp4) 2025-10-30 05:13 PDT, Jozef	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Anuj Panta

Comment 1 2025-10-30 17:48:30 PDT

After some investigation we found that opening the timeline tab within the WI and running this actually lets the the tokens parse, it seems when other tabs are open and we try the full payload we see a large memory issue

Radar WebKit Bug Importer

Comment 2 2025-11-06 04:14:11 PST

<rdar://problem/164162234>

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