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Medium · 5.5 CVE-2026-102734 EUVD-2026-98813GHSA-9w56-46f6-3qhx

asteval sandbox escape: arbitrary native memory read/write via numpy ctypes in default asteval Interpreter

Published Oct 13, 2026 · Updated Oct 13, 2026 · Assigned by GitHub_M

Description

asteval is a Python expression evaluator designed for restricted execution. Prior to 1.0.9, in asteval/astutils.py, the default Interpreter with numpy enabled exposes a ctypes type and permits from_address memory access. safe_getattr blocks the ctypes module but not reachable ctypes type objects, while attribute assignments use unfiltered setattr instead of safe_setattr. An attacker-controlled expression can derive an address with id, read memory through from_address, and write through an attribute assignment. The expression can read or corrupt arbitrary process memory, escape the intended sandbox, execute code, disclose secrets, or crash the host process. This issue is fixed in version 1.0.9.

Affected products

VendorProductAffectedFixed
lmfit asteval < 1.0.9 —

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 python-asteval No fix yet —
Debian 13 python-asteval No fix yet —
Debian 12 python-asteval No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 python-asteval No fix yet —
Ubuntu 26.04 LTS python-asteval No fix yet —
Ubuntu 24.04 LTS python-asteval No fix yet —
Ubuntu 22.04 LTS python-asteval No fix yet —
Ubuntu 20.04 LTS python-asteval No fix yet —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI asteval < 1.0.9 1.0.9 GHSA-9w56-46f6-3qhx

References