// For flags

CVE-2019-18277

haproxy: HTTP request smuggling issue with transfer-encoding header containing an obfuscated "chunked" value

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A flaw was found in HAProxy before 2.0.6. In legacy mode, messages featuring a transfer-encoding header missing the "chunked" value were not being correctly rejected. The impact was limited but if combined with the "http-reuse always" setting, it could be used to help construct an HTTP request smuggling attack against a vulnerable component employing a lenient parser that would ignore the content-length header as soon as it saw a transfer-encoding one (even if not entirely valid according to the specification).

Se encontró un fallo en HAProxy versiones anteriores a 2.0.6. En el modo legacy, los mensajes caracterizados por un encabezado de codificación de transferencia que no tenía el valor "chunked" no habían sido rechazados correctamente. El impacto fue limitado, pero si se combina con la configuración "http-reuse always", podría usarse para ayudar a construir un ataque de tráfico no autorizado de peticiones HTTP contra un componente vulnerable que emplee un analizador permisivo que ignore el encabezado de longitud de contenido tan pronto como se visualice uno de codificación de transferencia (incluso si no es completamente válido de acuerdo con la especificación).

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2019-10-23 CVE Reserved
  • 2019-10-23 CVE Published
  • 2024-02-16 EPSS Updated
  • 2024-08-05 CVE Updated
  • 2024-08-05 First Exploit
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
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
Haproxy
Search vendor "Haproxy"
 Haproxy
Search vendor "Haproxy" for product "Haproxy"
 < 2.0.6
Search vendor "Haproxy" for product "Haproxy" and version " < 2.0.6"
-
Affected