Vulnerability in CPython for Windows (June 22, 2026)

unknownCVE-2026-12003

A vulnerability has been discovered in CPython for Windows. It allows an attacker to cause a breach of data confidentiality and a bypass of the security policy.

CSIRTS triage

vendor: Python Software Foundation product: CPython Information disclosure Authentication bypass

What: A vulnerability in CPython for Windows can lead to data confidentiality breaches and security policy bypass.
Who is affected: Deployments of CPython on Windows are affected.
Urgency: Remediation is urgent due to the potential for unauthorized access.
Action: Update to the latest version of CPython.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-FR Avis de sécurité (FR · national-cert · site)
Severity: unknown
Published: 2026-06-22
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0790/

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-120030.14% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-12003	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] CPython: Multiple vulnerabilitiescert-bund
unknownCVE-2026-12003: CPython >3.11 Insecure Input Validation resulting in privilege escalationmsrc