CVE-2021-43797 HTTP fails to validate against control chars in header names which may lead to HTTP request smuggling

2021-12-0900:00:00

CWE-444

GitHub_M

www.cve.org

cve-2021-43797

http request smuggling

netty 4.1.71.final

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

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

AI Score

7.2

Confidence

High

EPSS

0.003

Percentile

69.2%

JSON

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. Netty prior to version 4.1.71.Final skips control chars when they are present at the beginning / end of the header name. It should instead fail fast as these are not allowed by the spec and could lead to HTTP request smuggling. Failing to do the validation might cause netty to “sanitize” header names before it forward these to another remote system when used as proxy. This remote system can’t see the invalid usage anymore, and therefore does not do the validation itself. Users should upgrade to version 4.1.71.Final.

CNA Affected

[
  {
    "vendor": "netty",
    "product": "netty",
    "versions": [
      {
        "version": "<= 4.1.7.0.Final",
        "status": "affected"
      }
    ]
  }
]