Subject: [ASA-202107-38] firefox-ublock-origin: denial of service

Arch Linux Security Advisory ASA-202107-38
==========================================

Severity: Medium
Date    : 2021-07-20
CVE-ID  : CVE-2021-36773
Package : firefox-ublock-origin
Type    : denial of service
Remote  : Yes
Link    : https://security.archlinux.org/AVG-2172

Summary
=======

The package firefox-ublock-origin before version 1.36.2-1 is vulnerable
to denial of service.

Resolution
==========

Upgrade to 1.36.2-1.

# pacman -Syu "firefox-ublock-origin>=1.36.2-1"

The problem has been fixed upstream in version 1.36.2.

Workaround
==========

None.

Description
===========

uBlock Origin before 1.36.2 supports an arbitrary depth of parameter
nesting for strict blocking, which allows crafted web sites to cause a
denial of service (unbounded recursion that can trigger memory
consumption and a loss of all blocking functionality).

Impact
======

A crafted web site could consume a lot of memory, disabling all
blocking functionality.

References
==========

https://github.com/vtriolet/writings/blob/main/posts/2021/ublock_origin_and_umatrix_denial_of_service.adoc
https://github.com/uBlockOrigin/uBlock-issues/issues/1649
https://github.com/gorhill/uBlock/commit/365b20e8cc27cd776ef3868b02ea739ba387356d
https://security.archlinux.org/CVE-2021-36773