title: Uncaught Exception (due to a data race) leads to process termination in Waitress
description: Waitress is a Web Server Gateway Interface server for Python 2 and 3. Waitress versions 2.1.0 and 2.1.1 may terminate early due to a thread closing a socket while the main thread is about to call select(). This will lead to the main thread raising an exception that is not handled and then causing the entire application to be killed. This issue has been fixed in Waitress 2.1.2 by no longer allowing the WSGI thread to close the socket. Instead, that is always delegated to the main thread. There is no work-around for this issue. However, users using waitress behind a reverse proxy server are less likely to have issues if the reverse proxy always reads the full response.
problem types: CWE-248: Uncaught Exception
affected:
{
product: waitress
vendor: Pylons
versions:
status: affected, version: >= 2.1.0, < 2.1.2
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 6.5
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]