Resource Exhaustion The advisory has been revoked - it doesn't affect any version of package waitress  (opens in a new tab)


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EPSS
2.36% (83rd percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-WAITRESS-544170
  • published4 Feb 2020
  • disclosed4 Feb 2020

Introduced: 4 Feb 2020

CVE-2020-5236  (opens in a new tab)
CWE-400  (opens in a new tab)

Amendment

The Debian security team deemed this advisory irrelevant for Debian:unstable.

NVD Description

Note: Versions mentioned in the description apply only to the upstream waitress package and not the waitress package as distributed by Debian.

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.