Security Advisory
CVE-2021-29991
8.1
HIGH
Vulnerability 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.
Published Date
November 3, 2021
Official Source
NIST NVD Advisory