Dark Reader is an accessibility browser extension that makes web pages colors dark. The dynamic dark mode feature of the extension works by analyzing the colors of web pages found in CSS style sheet files. In order to analyze cross-origin style sheets (stored on websites different from the original web page), Dark Reader requests such files via a background worker, ensuring the request is performed with no credentials and that the content type of the response is a CSS file. Prior to Dark Reader 4.9.117, this style content was assigned to an HTML Style Element in order to parse and loop through style declarations, and also stored in page's Session Storage for performance gains. This could allow a website author to request a style sheet from a locally running web server, for example by having a link pointing to `http[:]//localhost[:]8080/style[.]css`. The brute force of the host name, port and file name would be unlikely due to performance impact, that would cause the browser tab to hang shortly, but it could be possible to request a style sheet if the full URL was known in advance. As per December 18, 2025 there is no known exploit of the issue. The problem has been fixed in version 4.9.117 on December 3, 2025. The style sheets are now parsed using modern Constructed Style Sheets API and the contents of cross-origin style sheets is no longer stored in page's Session Storage. Version 4.9.118 (December 8, 2025) restricts cross-origin requests to localhost aliases, IP addresses, hosts with ports and non-HTTPS resources. The absolute majority of users have received an update 4.1.117 or 4.9.118 automatically within a week. However users must ensure their automatic updates are not blocked and they are using the latest version of the extension by going to chrome://extensions or about:addons pages in browser settings. Users utilizing manual builds must upgrade to version 4.9.118 and above. Developers using `darkreader` NPM package for their own websites are likely not affected, but must ensure the function passed to `setFetchMethod()` for performing cross-origin requests works within the intended scope. Developers using custom forks of earlier versions of Dark Reader to build other extensions or integrating into their apps or browsers must ensure they perform cross-origin requests safely and the responses are not accessible outside of the app or extension.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Dark Reader is an accessibility browser extension that makes web pages colors dark. The dynamic dark mode
    feature of the extension works by analyzing the colors of web pages found in CSS style sheet files. In
    order to analyze cross-origin style sheets (stored on websites different from the original web page), Dark
    Reader requests such files via a background worker, ensuring the request is performed with no credentials
    and that the content type of the response is a CSS file. Prior to Dark Reader 4.9.117, this style content
    was assigned to an HTML Style Element in order to parse and loop through style declarations, and also
    stored in page's Session Storage for performance gains. This could allow a website author to request a
    style sheet from a locally running web server, for example by having a link pointing to
    `http[:]//localhost[:]8080/style[.]css`. The brute force of the host name, port and file name would be
    unlikely due to performance impact, that would cause the browser tab to hang shortly, but it could be
    possible to request a style sheet if the full URL was known in advance. As per December 18, 2025 there is
    no known exploit of the issue. The problem has been fixed in version 4.9.117 on December 3, 2025. The
    style sheets are now parsed using modern Constructed Style Sheets API and the contents of cross-origin
    style sheets is no longer stored in page's Session Storage. Version 4.9.118 (December 8, 2025) restricts
    cross-origin requests to localhost aliases, IP addresses, hosts with ports and non-HTTPS resources. The
    absolute majority of users have received an update 4.1.117 or 4.9.118 automatically within a week. However
    users must ensure their automatic updates are not blocked and they are using the latest version of the
    extension by going to chrome://extensions or about:addons pages in browser settings. Users utilizing
    manual builds must upgrade to version 4.9.118 and above. Developers using `darkreader` NPM package for
    their own websites are likely not affected, but must ensure the function passed to `setFetchMethod()` for
    performing cross-origin requests works within the intended scope. Developers using custom forks of earlier
    versions of Dark Reader to build other extensions or integrating into their apps or browsers must ensure
    they perform cross-origin requests safely and the responses are not accessible outside of the app or
    extension. (CVE-2025-68467)

ID	Name	Product	Family	Severity
438334	SCA: security update for darkreader (GHSA-x369-mcw8-8rvj)	Tenable Cloud Security	SCA Checks	low
438334	SCA: security update for darkreader (GHSA-x369-mcw8-8rvj)	Tenable Self-Hosted Container Security	SCA Checks	low

Detections

Analytics

CVE-2025-68467

low

Tenable Plugins

low

low