Skip to content
Appaloosa Scout

Vulnerability · NVD

CVE-2021-29991

HIGH 8.1

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.

Attack vector : Network No privileges required
Show raw CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS 0.89% above median percentile 55.9%

Tracked apps referencing this CVE

For each app: the affected range, the fixing version, and where the tracked app stands today.

Vulnerable CPE configurations (1)
Vendor Product Versions
mozilla thunderbird
All platforms (wildcard)
<91.0.1
View on NVD ↗ Advisory · www.mozilla.org