CVE-2026-12003: CPython >3.11 Insecure Input Validation resulting in privilege escalation
CSIRTS triage
- What
- Insecure input validation in CPython can lead to privilege escalation.
- Who is affected
- Deployments of CPython versions greater than 3.11 are affected.
- Urgency
- Remediation is urgent due to the potential for privilege escalation.
- Action
- Upgrade to a secure version of CPython.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-12003
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
- unknownVulnerability in CPython for Windows (June 22, 2026)cert-fr-avis
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