VULNERABILITY INTELLIGENCE

CVE-2019-18277

CVSS score7.5 HIGH
EPSS probability10.07%
CISA KEVNot currently listed
Published2019-10-23
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Description

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).

Weakness classification

  • nvd@nist.gov: CWE-444

Primary references