CVE-2020-26959 Use after free in Firefox
A use-after-free vulnerability in Firefox and Thunderbird during shutdown allows attackers to cause memory corruption and potentially execute arbitrary code.
- 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-2020-26959?
CVE-2020-26959 is a high-severity use after free vulnerability in Mozilla Firefox, published on 9 Dec 2020. 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
During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
Weakness: CWE-416
Which versions are affected by CVE-2020-26959?
It affects 3 products.
Products include Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.
How do I fix CVE-2020-26959?
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-2020-26959 being exploited?
There is no known exploitation of CVE-2020-26959 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2020-26959, GHSA-w4gq-6hmw-x862, UBUNTU-CVE-2020-26959.