`EncryptingOutputStream` was susceptible to exposing uninitialized data. This issue could only be abused in order to write data to a local disk which may have implications for private browsing mode. This vulnerability affects Firefox ESR < 115.6 and Firefox < 121.
Severity
CVSS 3.1
6.5 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS
0.9% chance of exploitation in the next 30 days; higher than 59% of CVEs (scores of 2026-10-31)