RestrictedPython is a tool that helps define a subset of the Python language for accepting program input in a trusted environment. Prior to 8.4, RestrictedPython could allow a sandbox escape when a custom import policy or globals exposed the standard library string module, the string.Formatter class, a Formatter instance, or a Formatter subclass to restricted code. The string.Formatter methods format, get_field, get_value, and vformat performed attribute and item traversal internally without passing through RestrictedPython's safer_getattr protections. Restricted code could use those live object references to reach function globals, builtins, file access, or code execution primitives, affecting confidentiality, integrity, and availability in the host environment. This issue is fixed in version 8.4.

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Wed, 16 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Description RestrictedPython is a tool that helps define a subset of the Python language for accepting program input in a trusted environment. Prior to 8.4, RestrictedPython could allow a sandbox escape when a custom import policy or globals exposed the standard library string module, the string.Formatter class, a Formatter instance, or a Formatter subclass to restricted code. The string.Formatter methods format, get_field, get_value, and vformat performed attribute and item traversal internally without passing through RestrictedPython's safer_getattr protections. Restricted code could use those live object references to reach function globals, builtins, file access, or code execution primitives, affecting confidentiality, integrity, and availability in the host environment. This issue is fixed in version 8.4.
Title RestrictedPython: Sandbox escape via string.Formatter field resolution
Weaknesses CWE-200
CWE-470
CWE-680
CWE-693
References
Metrics cvssV3_1

{'score': 8.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-16T18:35:53.779Z

Reserved: 2026-08-19T19:52:28.214Z

Link: CVE-2026-76825

cve-icon Vulnrichment

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cve-icon NVD

Status : Deferred

Published: 2026-09-16T15:17:46.000

Modified: 2026-09-16T15:17:46.310

Link: CVE-2026-76825

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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