High (8.8). EPSS 2.8% chance of exploitation in the next 30 days.
An integer overflow can occur in the SwizzleData code while calculating buffer sizes. The overflowed value is used for subsequent graphics computations when their inputs are not sanitized which results in a potentially exploitable crash. This vulnerability affects Thunderbird < 60, Firefox ESR < 60.1, and Firefox < 61.
Severity
CVSS 3.0
8.8 high
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
2.8% chance of exploitation in the next 30 days; higher than 86% of CVEs (scores of 2026-10-31)