CVE-2019-18277

high

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).

References

https://git.haproxy.org/?p=haproxy-2.0.git;a=commit;h=196a7df44d8129d1adc795da020b722614d6a581

https://www.mail-archive.com/[email protected]/msg34926.html

https://nathandavison.com/blog/haproxy-http-request-smuggling

https://usn.ubuntu.com/4174-1/

http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00016.html

http://lists.opensuse.org/opensuse-security-announce/2019-12/msg00019.html

https://lists.debian.org/debian-lts-announce/2022/05/msg00045.html

Details

Source: MITRE

Published: 2019-10-23

Updated: 2022-06-02

Type: CWE-444

Risk Information

CVSS v2

Base Score: 4.3

Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N

Impact Score: 2.9

Exploitability Score: 8.6

Severity: MEDIUM

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Impact Score: 3.6

Exploitability Score: 3.9

Severity: HIGH