CVE-2019-9791 Memory corruption in Firefox
Type confusion in the IonMonkey JIT compiler allows arbitrary object reading and writing, potentially leading to code execution in Firefox and Thunderbird.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-9791?
CVE-2019-9791 is a critical memory corruption vulnerability in Mozilla Firefox, published on 26 Apr 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The type inference system allows the compilation of functions that can cause type confusions between arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor function is entered through on-stack replacement (OSR). This allows for possible arbitrary reading and writing of objects during an exploitable crash. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.
Weakness: CWE-843
Which versions are affected by CVE-2019-9791?
It affects 6 products.
Products include Mozilla Firefox, Mozilla Thunderbird, Redhat Enterprise Linux, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Tus.
How do I fix CVE-2019-9791?
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-2019-9791 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-9791 exists.
Public exploit code: 1 Exploit-DB entry and 1 proofs of concept on GitHub.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2019-9791, GHSA-9r58-49jg-hrq7, UBUNTU-CVE-2019-9791.