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OpenAdvisories
High · 8.3 CVE-2026-55830 EUVD-2026-42434GHSA-ffg3-p8fm-mjx2PYSEC-2026-3917

RestrictedPython guard hooks can be shadowed via positional-only arguments

Published Jul 8, 2026 · Updated Jul 9, 2026 · Assigned by GitHub_M

Description

RestrictedPython is a tool that helps to define a subset of the Python language which allows to provide a program input into a trusted environment. Prior to 8.3, check_function_argument_names() rejected protected guard hook names for regular, variadic, and keyword-only arguments but omitted positional-only arguments, allowing __getattr__, _getitem_, _write_, or _print_ to be shadowed by a local parameter and bypass the embedding application's access policy. This issue is fixed in version 8.3.

Affected products

VendorProductAffectedFixed
zopefoundation RestrictedPython < 8.3 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 restrictedpython 8.4-1 —
Debian 13 restrictedpython No fix yet —
Debian 12 restrictedpython No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS restrictedpython No fix yet —
Ubuntu 18.04 LTS restrictedpython No fix yet —
Ubuntu 16.04 LTS restrictedpython No fix yet —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 24.04 LTS restrictedpython No fix yet —
Ubuntu Pro 22.04 LTS restrictedpython No fix yet —
Ubuntu Pro 20.04 LTS restrictedpython No fix yet —

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling open-webui 0.11.0-r9 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI restrictedpython < 8.3 8.3 GHSA-ffg3-p8fm-mjx2

References