PT-2021-5250 · Mozilla+5 · Thunderbird+6
Youssef Sammouda
·
Published
2021-08-16
·
Updated
2024-12-12
·
CVE-2021-29991
CVSS v3.1
8.1
High
| Vector | AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N |
Name of the Vulnerable Software and Affected Versions
Firefox versions prior to 91.0.1
Thunderbird versions prior to 91.0.1
Description
The issue is related to the incorrect handling of HTTP requests, which can lead to a header splitting attack against servers using HTTP/3. This allows a remote attacker to perform cross-site scripting (XSS) attacks. The vulnerability affects Firefox and Thunderbird, and it is related to the incorrect interpretation of a newline in an HTTP/3 header as two separate headers.
Recommendations
For Firefox versions prior to 91.0.1, update to version 91.0.1 or later to resolve the issue.
For Thunderbird versions prior to 91.0.1, update to version 91.0.1 or later to resolve the issue.
As a temporary workaround, consider restricting access to servers using HTTP/3 to minimize the risk of exploitation.
Exploit
Fix
HTTP Request/Response Smuggling
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Weakness Enumeration
Related Identifiers
Affected Products
Alt Linux
Astra Linux
Firefox
Linuxmint
Suse
Thunderbird
Ubuntu