6.5
CVSSv3

CVE-2020-5236

Published: 04/02/2020 Updated: 06/02/2020
CVSS v2 Base Score: 6.8 | Impact Score: 6.9 | Exploitability Score: 8
CVSS v3 Base Score: 6.5 | Impact Score: 3.6 | Exploitability Score: 2.8
VMScore: 606
Vector: AV:N/AC:L/Au:S/C:N/I:N/A:C

Vulnerability Summary

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 malicious user 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.

Vulnerability Trend

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agendaless waitress 1.4.2

Github Repositories

Waitress 1.4.2 ReDoS - CVE-2020-5236 (Blog Sample Code)

Waitress 142 ReDoS - CVE-2020-5236 Waitress version 142 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

Fetches security vulnerabilities and creates pip-constraints based on them.

security-constraints Security-constraints is a command-line application used to fetch security vulnerabilities in Python packages from external sources and from them generate version constraints for the packages The constraints can then be given to pip install with the -c option, either on the command line or in a requirements file Installation Just install it with pip: pip i