CVE-2020-15654 Denial of service in Firefox

What is CVE-2020-15654?

CVE-2020-15654 is a medium-severity denial of service vulnerability in Canonical Ubuntu Linux, published on 10 Aug 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacting with the user interface, when they are not. This could lead to a perceived broken state, especially when interactions with existing browser dialogs and warnings do not work. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.

Weakness: CWE-835

Which versions are affected by CVE-2020-15654?

It affects 4 products.

Products include Canonical Ubuntu Linux, Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.

How do I fix CVE-2020-15654?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-15654 being exploited?

There is no known exploitation of CVE-2020-15654 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-8j7j-8w2r-72pq, UBUNTU-CVE-2020-15654.