Inconsistent interpretation of HTTP requests in waitress
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2019-16785 |
| CWE-ID | CWE-444 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
waitress Other software / Other software solutions |
| Vendor | Pylons Project |
Security Bulletin
This security bulletin contains one medium risk vulnerability.
1) Inconsistent interpretation of HTTP requests
EUVDB-ID: #VU33151
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2019-16785
CWE-ID:
CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')
Exploit availability: No
DescriptionThe vulnerability allows a remote non-authenticated attacker to manipulate data.
Waitress through version 1.3.1 implemented a "MAY" part of the RFC7230 which states: "Although the line terminator for the start-line and header fields is the sequence CRLF, a recipient MAY recognize a single LF as a line terminator and ignore any preceding CR." Unfortunately if a front-end server does not parse header fields with an LF the same way as it does those with a CRLF it can lead to the front-end and the back-end server parsing the same HTTP message in two different ways. This can lead to a potential for HTTP request smuggling/splitting whereby Waitress may see two requests while the front-end server only sees a single HTTP message. This issue is fixed in Waitress 1.4.0.
MitigationInstall update from vendor's website.
Vulnerable software versionswaitress: 1.4.0
External linkshttp://access.redhat.com/errata/RHSA-2020:0720
http://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes
http://github.com/Pylons/waitress/commit/8eba394ad75deaf9e5cd15b78a3d16b12e6b0eba
http://github.com/Pylons/waitress/security/advisories/GHSA-pg36-wpm5-g57p
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
