Bug 1995267 (CVE-2021-29991)

Summary:	CVE-2021-29991 Mozilla: Header Splitting possible with HTTP/3 Responses
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	erack, jhorak, nobody, stransky, tpopela
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1996585, 1996586, 1996588, 1996589, 1996590, 1996591, 1996592, 1996593, 1996594, 1996595, 1996596, 1996597
Bug Blocks:	1995268

Description Pedro Sampaio 2021-08-18 17:24:29 UTC

Firefox incorrectly accepted a newline in a HTTP/3 header, interpreting it as two separate headers. This allowed for a header splitting attack against servers using HTTP/3.

References:

https://www.mozilla.org/en-US/security/advisories/mfsa2021-37/