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HTTP Request Smuggling The advisory has been revoked - it doesn't affect any version of package haproxy.src  (opens in a new tab)

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EPSS
0.97% (77th percentile)

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  • Snyk IDSNYK-RHEL10-HAPROXYSRC-12614698
  • published11 Sept 2025
  • disclosed13 Sept 2019
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Introduced: 13 Sep 2019

CVE-2019-18277  (opens in a new tab)
CWE-444  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream haproxy.src package and not the haproxy.src package as distributed by RHEL.

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).