SB2021081805 - HTTP response splitting in Mozilla Firefox and Thunderbird
Published: August 18, 2021
Security Bulletin ID
SB2021081805
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) HTTP response splitting (CVE-ID: CVE-2021-29991)
CWE-ID: CWE-113 - Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote attacker to perform HTTP splitting attacks.
The vulnerability exists due to the affected software incorrectly accepts a newline in a HTTP/3 header, interpretting it as two separate headers. A remote attacker can perform a header splitting attack against servers using HTTP/3.
Remediation
Install update from vendor's website.