Use After Free in Mozilla Firefox

CVE-2020-12420

When trying to connect to a STUN server, a race condition could have caused a use-after-free of a pointer, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.10, Firefox < 78, and Thunderbird < 68.10.0.

Vulnerability class: Race Condition

EPSS: 0.019 (77.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2020-12420?
CVE-2020-12420 is a high-severity vulnerability in Mozilla Firefox, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 8.8/10. Published 2020-07-09.
How severe is CVE-2020-12420?
High severity. CVSS v3 base score is 8.8 out of 10.