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: 2021-11-03
Score: 8.1 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-16450 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.
Ubuntu USN Ubuntu USN USN-5047-1 Firefox vulnerability
Ubuntu USN Ubuntu USN USN-5248-1 Thunderbird vulnerabilities
History

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Mozilla Firefox Thunderbird
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2024-08-03T22:24:59.901Z

Reserved: 2021-04-01T00:00:00.000Z

Link: CVE-2021-29991

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-11-03T01:15:07.060

Modified: 2024-11-21T06:02:07.710

Link: CVE-2021-29991

cve-icon Redhat

Severity : Important

Publid Date: 2021-08-18T00:00:00Z

Links: CVE-2021-29991 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses