CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
EPSS
Percentile
32.8%
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.
[
{
"product": "Waitress",
"vendor": "Pylons",
"versions": [
{
"status": "affected",
"version": "= 1.4.2"
}
]
}
]