CPython CVE-2026-9669 enables remote DoS
A vulnerability in CPython allows attackers to trigger remote denial of service against unpatched systems.
The French national cybersecurity agency ANSSI has published an advisory warning of a denial-of-service vulnerability in CPython, tracked as CVE-2026-9669. The flaw affects CPython installations that have not applied the latest security patch.
The vulnerability permits remote attackers to cause a denial-of-service condition without requiring authentication or user interaction. The Python Software Foundation released security patches on June 8, 2026, addressing this issue across supported versions.
Organisations running Python-based applications and services should prioritise patching to mitigate the risk of service disruption. The advisory recommends consulting the official Python security bulletin for patch availability and deployment guidance.
Mentioned in this report
Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0704
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