CVE-2021-29981 Memory corruption in Firefox
A register confusion flaw in the JIT compiler allows attackers to cause crashes or potentially execute arbitrary code in Firefox and Thunderbird.
- 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-2021-29981?
CVE-2021-29981 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
An issue present in lowering/register allocation could have led to obscure but deterministic register confusion failures in JITted code that would lead to a potentially exploitable crash. This vulnerability affects Firefox < 91 and Thunderbird < 91.
Which versions are affected by CVE-2021-29981?
It affects 2 products.
Products include Mozilla Firefox, Mozilla Thunderbird.
How do I fix CVE-2021-29981?
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-2021-29981 being exploited?
There is no known exploitation of CVE-2021-29981 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as GHSA-fxr9-2j9j-f89c, UBUNTU-CVE-2021-29981.