An integer overflow can occur during conversion of text to some Unicode character sets due to an unchecked length parameter. This vulnerability affects Firefox ESR < 52.7 and Thunderbird < 52.7.
Severity
CVSS 3.0
7.3 high
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS
3.2% chance of exploitation in the next 30 days; higher than 88% of CVEs (scores of 2026-10-31)