CVEvulnerability

CVE-2020-5236

6.5 MEDIUM Published 2020-02-04 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2020-02-04
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
5.7 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
CVSS 3.1 ([email protected])
6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0 ([email protected])
6.8 MEDIUM — AV:N/AC:L/Au:S/C:N/I:N/A:C
Weaknesses
CWE-400

Description

Waitress version 1.4.2 allows a DOS attack When waitress receives a header that contains invalid characters. When a header like "Bad-header: xxxxxxxxxxxxxxx\x10" is received, it will cause the regular expression engine to catastrophically backtrack causing the process to use 100% CPU time and blocking any other interactions. This allows an attacker to send a single request with an invalid header and take the service offline. This issue was introduced in version 1.4.2 when the regular expression was updated to attempt to match the behaviour required by errata associated with RFC7230. The regular expression that is used to validate incoming headers has been updated in version 1.4.3, it is recommended that people upgrade to the new version of Waitress as soon as possible.

Affected configurations

• agendaless waitress 1.4.2

Related

Weakness · CWE (1)

  • CWE-400 Uncontrolled Resource Consumption weakness

References