// For flags

CVE-2019-16789

HTTP Request Smuggling in Waitress: Invalid whitespace characters in headers

Severity Score

8.2
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

In Waitress through version 1.4.0, if a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by Waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. If a front-end server does HTTP pipelining to a backend Waitress server this could lead to HTTP request splitting which may lead to potential cache poisoning or unexpected information disclosure. This issue is fixed in Waitress 1.4.1 through more strict HTTP field validation.

En Waitress versiones hasta 1.4.0, si un servidor proxy es usado frente a waitress, un atacante puede enviar una petición no comprobada que omita el front-end y que waitress analiza de manera diferente conllevando a un posible trafico no autorizado de peticiones HTTP. Waitress analizaría las peticiones especialmente diseñadas que contienen caracteres de espacio en blanco especiales en el encabezado Transfer-Encoding como si fuera una petición fragmentada, pero un servidor front-end usaría Content-Length en su lugar ya que el encabezado Transfer-Encoding es considerado no válido debido a que contiene caracteres no válidos. Si un servidor de aplicaciones para usuario establece una canalización HTTP hacia un servidor backend de Waitress, esto podría conllevar a una división de la petición HTTP, lo que podría generar un posible envenenamiento de la caché o una divulgación inesperada de información. Este problema se soluciona en Waitress versión 1.4.1 por medio de una comprobación del campo HTTP más estricta.

An HTTP-interpretation flaw was found in waitress, through version 1.4.0. If a proxy server is used in front of waitress, an invalid request may be sent by an attacker that bypasses the front-end and is parsed differently by waitress leading to a potential for HTTP request smuggling. Specially crafted requests containing special whitespace characters in the Transfer-Encoding header would get parsed by waitress as being a chunked request, but a front-end server would use the Content-Length instead as the Transfer-Encoding header is considered invalid due to containing invalid characters. If a front-end server does HTTP pipelining to a backend Waitress server, an HTTP request splitting could occur which may lead to potential cache poisoning or unexpected information disclosure. This issue is fixed in Waitress 1.4.1 through more strict HTTP field validation. The highest threat from this vulnerability is data integrity.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2019-09-24 CVE Reserved
  • 2019-12-26 CVE Published
  • 2024-04-20 EPSS Updated
  • 2024-08-05 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Agendaless
Search vendor "Agendaless"
Waitress
Search vendor "Agendaless" for product "Waitress"
<= 1.4.0
Search vendor "Agendaless" for product "Waitress" and version " <= 1.4.0"
-
Affected
Oracle
Search vendor "Oracle"
Communications Cloud Native Core Network Function Cloud Native Environment
Search vendor "Oracle" for product "Communications Cloud Native Core Network Function Cloud Native Environment"
1.10.0
Search vendor "Oracle" for product "Communications Cloud Native Core Network Function Cloud Native Environment" and version "1.10.0"
-
Affected
Debian
Search vendor "Debian"
Debian Linux
Search vendor "Debian" for product "Debian Linux"
9.0
Search vendor "Debian" for product "Debian Linux" and version "9.0"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
Fedora
Search vendor "Fedoraproject" for product "Fedora"
30
Search vendor "Fedoraproject" for product "Fedora" and version "30"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
Fedora
Search vendor "Fedoraproject" for product "Fedora"
31
Search vendor "Fedoraproject" for product "Fedora" and version "31"
-
Affected
Redhat
Search vendor "Redhat"
Openstack
Search vendor "Redhat" for product "Openstack"
15
Search vendor "Redhat" for product "Openstack" and version "15"
-
Affected