CVE-2019-16785

HIGH EPSS 84.1%
Published Dec 20, 20196y ago · Modified Jun 17, 20262w ago
7.5 CVSS 3.1
High
Find Similar
Published Dec 20, 2019 6y ago
Last Modified Jun 17, 2026 2w ago

Description

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.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
84.1% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-444

Affected Products 6

VendorProductVersionRange
agendalesswaitress* ≤1.3.1
oraclecommunications_cloud_native_core_network_function_cloud_native_environment1.10.0any
debiandebian_linux9.0any
fedoraprojectfedora30any
fedoraprojectfedora31any
redhatopenstack15any

References 8

  • access.redhat.com https://access.redhat.com/errata/RHSA-2020:0720
    Third Party Advisory
  • docs.pylonsproject.org https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes
    Vendor Advisory
  • github.com https://github.com/Pylons/waitress/commit/8eba394ad75deaf9e5cd15b78a3d16b12e6b0eba
    PatchThird Party Advisory
  • github.com https://github.com/Pylons/waitress/security/advisories/GHSA-pg36-wpm5-g57p
    ExploitThird Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html
    Mailing ListThird Party Advisory
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GVDHR2DNKCNQ7YQXISJ45NT4IQDX3LJ7/
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LYEOTGWJZVKPRXX2HBNVIYWCX73QYPM5/
  • oracle.com https://www.oracle.com/security-alerts/cpuapr2022.html
    PatchThird Party Advisory

Remediation

  • github.com https://github.com/Pylons/waitress/commit/8eba394ad75deaf9e5cd15b78a3d16b12e6b0eba
    PatchThird Party Advisory
  • oracle.com https://www.oracle.com/security-alerts/cpuapr2022.html
    PatchThird Party Advisory