CVE-2020-12391 Security feature bypass in Firefox

What is CVE-2020-12391?

CVE-2020-12391 is a high-severity vulnerability in Mozilla Firefox, published on 26 May 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Documents formed using data: URLs in an OBJECT element failed to inherit the CSP of the creating context. This allowed the execution of scripts that should have been blocked, albeit with a unique opaque origin. This vulnerability affects Firefox < 76.

Weakness: CWE-863

Which versions are affected by CVE-2020-12391?

It affects 1 product.

Products include Mozilla Firefox.

How do I fix CVE-2020-12391?

Upgrade to a fixed version.

Is CVE-2020-12391 being exploited?

There is no known exploitation of CVE-2020-12391 in the wild and no public exploit code.

Other vulnerabilities in Mozilla Firefox

• CVE-2019-11708 Mozilla Firefox and Thunderbird Sandbox Escape Exploited Critical 10.0
• CVE-2010-3765 Mozilla Multiple Products Remote Code Execution Exploited Critical 9.8
• CVE-2022-26486 Mozilla Firefox Use-After-Free Exploited Critical 9.6
• CVE-2022-26485 Mozilla Firefox Use-After-Free Exploited High 8.8
• CVE-2019-11707 Mozilla Firefox and Thunderbird Type Confusion Exploited High 8.8

All Mozilla Firefox vulnerabilities

Sources

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

Also known as GHSA-cxc7-m7pw-q6p7, UBUNTU-CVE-2020-12391.