CVE-2018-5143 Cross-site scripting in Firefox

What is CVE-2018-5143?

CVE-2018-5143 is a medium-severity cross-site scripting vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. 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

URLs using "javascript:" have the protocol removed when pasted into the addressbar to protect users from cross-site scripting (XSS) attacks, but if a tab character is embedded in the "javascript:" URL the protocol is not removed and the script will execute. This could allow users to be socially engineered to run an XSS attack against themselves. This vulnerability affects Firefox < 59.

Weakness: CWE-79

Which versions are affected by CVE-2018-5143?

It affects 2 products.

Products include Canonical Ubuntu Linux, Mozilla Firefox.

How do I fix CVE-2018-5143?

Upgrade to a fixed version.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2018-5143 being exploited?

There is no known exploitation of CVE-2018-5143 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-qqw6-4m7h-4hwr, UBUNTU-CVE-2018-5143.