CVE-2020-26959

HIGH

Firefox <83, Firefox ESR <78.5, Thunderbird <78.5 - Use After Free

Title source: llm
STIX 2.1

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.

References (4)

Core 4
Core References
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1669466
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-50/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-52/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-51/

Scores

CVSS v3 8.8
EPSS 0.0050
EPSS Percentile 65.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

CWE
CWE-416
Status published
Products (3)
mozilla/firefox < 83.0
mozilla/firefox_esr < 78.5
mozilla/thunderbird < 78.5
Published Dec 09, 2020
Tracked Since Feb 18, 2026