CVE-2022-31015

Uncaught Exception (due to a data race) leads to process termination in Waitress

MEDIUM
5.9
CVSS Score
Published: May 31, 2022 at 10:50 PM UTC
Updated: June 17, 2026 at 04:44 AM UTC
2 products affected across 2 vendorsWaitressWaitress

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Severity
MEDIUM5.9
Exploit prediction
EPSS 1%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.1.0 ≤ v < 2.1.2
Affected range stops below 2.1.2, so it looks safe — our inference, not a vendor statement
v < 2.1.2
Affected range stops below 2.1.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_MISCExploitIssue TrackingPatchThird Party Advisory
https://github.com/Pylons/waitress/issues/374
x_refsource_MISCIssue TrackingPatchThird Party Advisory
https://github.com/Pylons/waitress/pull/377

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-248CWE-362

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