Use After Free in Mozilla Firefox
CVE-2020-26959
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.
Vulnerability class: Use-After-Free
EPSS: 0.013 (66.8th 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
- Mozilla Firefox — versions < 83
- Mozilla Firefox Esr — versions < 78.5
- Mozilla Firefox_esr
- Mozilla Thunderbird — versions < 78.5
Weakness classification (CWE)
References
- security@mozilla.org (Permissions Required, x_refsource_MISC, Issue Tracking, Vendor Advisory)
- security@mozilla.org (x_refsource_CONFIRM, Vendor Advisory)
- security@mozilla.org (x_refsource_CONFIRM, Vendor Advisory)
- security@mozilla.org (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-26959?
- CVE-2020-26959 is a high-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 8.8/10. Published 2020-12-09.
- How severe is CVE-2020-26959?
- High severity. CVSS v3 base score is 8.8 out of 10.