CVE-2019-9821 Use after free in Firefox
A use-after-free race condition in Firefox shared workers allows attackers to cause a crash or potentially execute arbitrary code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-9821?
CVE-2019-9821 is a high-severity use after free vulnerability in Mozilla Firefox, published on 23 Jul 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A use-after-free vulnerability can occur in AssertWorkerThread due to a race condition with shared workers. This results in a potentially exploitable crash. This vulnerability affects Firefox < 67.
Which versions are affected by CVE-2019-9821?
It affects 1 product.
Products include Mozilla Firefox.
How do I fix CVE-2019-9821?
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-2019-9821 being exploited?
There is no known exploitation of CVE-2019-9821 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as GHSA-f9x2-983g-532w, UBUNTU-CVE-2019-9821.