Description
Firefox incorrectly accepted a newline in a HTTP/3 header, interpretting it as two separate headers. This allowed for a header splitting attack against servers using HTTP/3. This vulnerability affects Firefox < 91.0.1 and Thunderbird < 91.0.1.
Scores
CVSS v3
8.1
EPSS
0.0034
EPSS Percentile
56.8%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Details
CWE
CWE-444
Status
published
Products (2)
mozilla/firefox
< 91.0.1
mozilla/thunderbird
< 91.0.1
Published
Nov 03, 2021
Tracked Since
Feb 18, 2026