CVE-2021-29991

CVSS V2 Medium 5.8 CVSS V3 High 8.1

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.

Overview

CVE ID
CVE-2021-29991

Assigner
security@mozilla.org

Vulnerability Status
Analyzed

Published Version
2021-11-03T01:15:07

Last Modified Date
2021-11-04T21:01:32

Weakness Enumerations

CWE	URL
CWE-444	http://cwe.mitre.org/data/definitions/444.html

CPE Configuration (Product)

CPE	Vulnerable	Operator	Version Start	Version End
cpe:2.3:a:mozilla:firefox::::::::	1	OR		91.0.1
cpe:2.3:a:mozilla:thunderbird::::::::	1	OR		91.0.1

CVSS Version 2

Version
2.0

Vector String
AV:N/AC:M/Au:N/C:P/I:P/A:N

Access Vector
NETWORK

Access Compatibility
MEDIUM

Authentication
NONE

Confidentiality Impact
PARTIAL

Integrity Impact
PARTIAL

Availability Impact
NONE

Base Score
5.8

Severity
MEDIUM

Exploitability Score
8.6

Impact Score
4.9

CVSS Version 3

Version
3.1

Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack Vector
NETWORK

Attack Compatibility
LOW

Privileges Required
NONE

User Interaction
REQUIRED

Scope
UNCHANGED

Confidentiality Impact
HIGH

Availability Impact
NONE

Base Score
8.1

Base Severity
HIGH

Exploitability Score
2.8

Impact Score
5.2

References

Reference URL	Reference Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1724896	Permissions Required
https://www.mozilla.org/security/advisories/mfsa2021-37/	Vendor Advisory

Sources

Source Name	Source URL
NIST	https://nvd.nist.gov/vuln/detail/CVE-2021-29991
MITRE	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29991

History

Created	Old Value	New Value	Data Type	Notes
2022-05-10 06:48:16				Added to TrackCVE
2022-12-05 13:44:25	2021-11-03T01:15Z	2021-11-03T01:15:07	CVE Published Date	updated
2022-12-05 13:44:25		2021-11-04T21:01:32	CVE Modified Date	updated
2022-12-05 13:44:25		Analyzed	Vulnerability Status	updated