CVE-2020-12387 Use after free in Firefox
A race condition in Web Worker shutdown causes a use-after-free, potentially allowing attackers to execute arbitrary code or crash the browser.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-12387?
CVE-2020-12387 is a high-severity use after free 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
A race condition when running shutdown code for Web Worker led to a use-after-free vulnerability. This resulted in a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.8, Firefox < 76, and Thunderbird < 68.8.0.
Which versions are affected by CVE-2020-12387?
It affects 3 products.
Products include Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.
How do I fix CVE-2020-12387?
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-2020-12387 being exploited?
There is no known exploitation of CVE-2020-12387 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2020-12387, GHSA-8m69-jh8v-xjx3, UBUNTU-CVE-2020-12387.