Chrome · Extensions
CVE-2025-12436
Logic Error in Extensions
Overview
Medium
Severity
—
CVSS
No
Exploited ITW
Fixed
Fix Status
Files Changed
extensions/docs/security_faq.md
Patch
From 2061e6224f53dfff08dc3117c860e6b9e4d658ee Mon Sep 17 00:00:00 2001 From: Devlin Cronin <[email protected]> Date: Wed, 17 Sep 2025 16:43:14 -0700 Subject: [PATCH] [Extensions] Update debugger API entry in security FAQ Bug: 40054742 Change-Id: I6e91b89e2b075eb16e8567b5c76ea8da3364fb30 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6961403 Commit-Queue: Devlin Cronin <[email protected]> Reviewed-by: Chris Thompson <[email protected]> Cr-Commit-Position: refs/heads/main@{#1516943} --- diff --git a/extensions/docs/security_faq.md b/extensions/docs/security_faq.md index ba9895d..11e9549f 100644 --- a/extensions/docs/security_faq.md +++ b/extensions/docs/security_faq.md @@ -421,10 +421,17 @@ ### What privileges does the Debugger permission grant an extension? What privileges should it lack? -The debugger permission should grant an extension the power to automate any -website. This may extend to driving interactions with that site which are not -possible using JavaScript on the site itself, but instead normally require -user interaction with Chrome features. +The debugger permission grants an extension with access to the Chrome DevTools +Protocol, which is a powerful API surface that has many different capabilities. +This allows an extension to automate or debug any website, and may extend to +driving interactions with that site which are not possible using JavaScript on +the site itself, but instead normally require user interaction with Chrome +features. + +Through the use of certain methods in the Chrome DevTools Protocol, the +debugger API *may* in some cases also sidestep other typical restrictions, such +as host permissions or file access. This is the reason for the broad security +warning associated with the debugger API. The debugger permission does not allow automating parts of the Chromium browser unrelated to websites. Automating WebUI or settings, installing
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Original Bug Report
reported by [email protected]
Reading local files through an extension that doesn't have the file permission
VULNERABILITY DETAILS
The “tabCapture” permission allows capturing the visible area of a given tab, but doesn’t seem to block the capture when the tab gets redirected to a local file - which allows an attacker to leak its contents even though the file permission was not given.
VERSION
Chrome Version: 88.0.4324.150 (Official Build) (64-bit)
Operating System: Windows 10
REPRODUCTION CASE
- Download extension.zip and load it into Chrome.
- Make sure you have the file permission disabled for the extension.
- Click on the extension’s icon on the Chrome toolbar.
- After a few seconds, the contents of file:///C:/ will be shown inside a video tag. This information can be exfiltrated to the attacker’s server.
Here’s an unlisted video demonstrating the issue:
https://youtu.be/sKfKbhOLDKo
CREDIT INFORMATION
Reporter credit: Luan Herrera (@lbherrera_)
References
On This Page