CPython: sandbox escape

CPython

A sandbox escape vulnerability was found in CPython.

Do this now

Check the CPython advisory for a fix and restrict access to affected sandboxed code meanwhile.

Who should check: teams running Python

First seen: 5 Nov 2026
Last update: 5 Nov 2026, 21:17 UTC
Source: news
On the menu as: Python

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## CPython: sandbox escape
Severity: unknown. Patch status: fix status unknown.
Affected: CPython

A sandbox escape vulnerability was found in CPython.

## Steps
1. Search the repo, its CI and infra config for CPython. If present, report the version in use and whether it's affected.
2. No source names a fix yet; check the vendor advisory. Until one ships: restrict network access to it.

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://seclists.org/oss-sec/2026/q4/530 https://seclists.org/oss-sec/2026/q4/531
https://pwned.coffee/i/cpython-sandbox-escape

Timeline

5 Nov 2026, 21:17 UTC
Reported by seclists.org: Re: CPython sandbox escape
5 Nov 2026, 20:18 UTC
Fix status: no fix yet → unknown.
5 Nov 2026
First reported.

Receipt

Exploitation: No known exploitation
Score: No CVSS published yet: severity unknown.
Last checked: 6 Nov 2026, 12:18 UTC

Sources: KEV – CVE record – Vendor –

Sources

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