CVE-2019-18277: haproxy

Vulnerability summary

CVE-2019-18277 is a high (CVSS 7.5) vulnerability in haproxy. EPSS estimates a 10.07% chance of exploitation in the next 30 days, higher than 95.6% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 23-10-2019
   PublishedVulnerability first disclosed.
2. 05-08-2024
   Last modifiedVulnerability information updated.

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).

• CWE-444Inconsistent Interpretation of HTTP RequestsThe product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.