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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.013 (69.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 69.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: +0.000
Affected products
- Mozilla Firefox — versions < 83
- Mozilla Firefox Esr — versions < 78.5
- Mozilla Firefox Esr
- Mozilla Thunderbird — versions < 78.5
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking, Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2020-50/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2020-52/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2020-51/ (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.