CVE-2019-11757 Use after free in Firefox

What is CVE-2019-11757?

CVE-2019-11757 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 8 Jan 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 following the value's prototype chain, it was possible to retain a reference to a locale, delete it, and subsequently reference it. This resulted in a use-after-free and a potentially exploitable crash. This vulnerability affects Firefox < 70, Thunderbird < 68.2, and Firefox ESR < 68.2.

Weakness: CWE-416

Which versions are affected by CVE-2019-11757?

It affects 4 products.

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

How do I fix CVE-2019-11757?

Upgrade to a fixed version.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2019-11757 being exploited?

There is no known exploitation of CVE-2019-11757 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 DEBIAN-CVE-2019-11757, GHSA-fxjq-wqq4-mf6x, UBUNTU-CVE-2019-11757.