Risk | Medium |
Patch available | YES |
Number of vulnerabilities | 1 |
CVE-ID | CVE-2021-29991 |
CWE-ID | CWE-113 |
Exploitation vector | Network |
Public exploit | N/A |
Vulnerable software Subscribe |
Mozilla Firefox Client/Desktop applications / Web browsers Mozilla Thunderbird Client/Desktop applications / Messaging software |
Vendor | Mozilla |
Security Bulletin
This security bulletin contains one medium risk vulnerability.
EUVDB-ID: #VU55935
Risk: Medium
CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-29991
CWE-ID:
CWE-113 - Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
Exploit availability: No
DescriptionThe 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.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMozilla Firefox: 80.0 - 91.0
Mozilla Thunderbird: 91.0
External linkshttp://www.mozilla.org/en-US/security/advisories/mfsa2021-37/
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to trick the victim to visit a specially crafted website.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.