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USN-4942-1: Firefox vulnerability

10 May 2021

Firefox could be made to crash or run programs as your login if it opened a malicious website.



  • firefox - Mozilla Open Source web browser


A race condition was discovered in Web Render Components. If a user were
tricked into opening a specially crafted website, an attacker could
potentially exploit this to execute arbitrary code.

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 21.04
Ubuntu 20.10
Ubuntu 20.04
Ubuntu 18.04

After a standard system update you need to restart Firefox to make
all the necessary changes.