CVE-2021-43539 Use after free in Firefox
A use-after-free vulnerability in Firefox and Thunderbird allows attackers to cause a crash or potentially execute arbitrary code via crafted WebAssembly instances.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-43539?
CVE-2021-43539 is a high-severity use after free vulnerability in Debian Debian Linux, published on 8 Dec 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
Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live pointers. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.
Weakness: CWE-416
Which versions are affected by CVE-2021-43539?
It affects 4 products.
Products include Debian Debian Linux, Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.
How do I fix CVE-2021-43539?
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-2021-43539 being exploited?
There is no known exploitation of CVE-2021-43539 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2021-43539, GHSA-cx8r-rrrj-cfxg, UBUNTU-CVE-2021-43539.