CVE-2021-29984 Memory corruption in Firefox

What is CVE-2021-29984?

CVE-2021-29984 is a high-severity memory corruption vulnerability in Mozilla Firefox, published on 17 Aug 2021. 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

Instruction reordering resulted in a sequence of instructions that would cause an object to be incorrectly considered during garbage collection. This led to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 78.13, Thunderbird < 91, Firefox ESR < 78.13, and Firefox < 91.

Weakness: CWE-787

Which versions are affected by CVE-2021-29984?

It affects 3 products.

Products include Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.

How do I fix CVE-2021-29984?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-29984 being exploited?

There is no known exploitation of CVE-2021-29984 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 DEBIAN-CVE-2021-29984, GHSA-9qg9-jm6v-8f8r, UBUNTU-CVE-2021-29984, openSUSE-SU-2024:11059-1.