---
id: CVE-2026-102734
title: asteval is a Python expression evaluator designed for restricted execution
summary: >-
  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 blo…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cwe:
  - CWE-693
  - CWE-749
  - CWE-913
vendor: lmfit
product: asteval
affected:
  - asteval < 1.0.9
patched:
  - asteval 1.0.9
published: '2026-10-13'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:04:29.760'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102734'
references:
  - url: >-
      https://github.com/lmfit/asteval/commit/a3e56e7f8ed567a4817684d94213b290359077b4
    label: security-advisories@github.com
  - url: 'https://github.com/lmfit/asteval/pull/153'
    label: security-advisories@github.com
  - url: 'https://github.com/lmfit/asteval/releases/tag/1.0.9'
    label: security-advisories@github.com
  - url: 'https://github.com/lmfit/asteval/security/advisories/GHSA-9w56-46f6-3qhx'
    label: security-advisories@github.com
  - url: 'https://github.com/lmfit/asteval'
tags:
  - nvd
  - cve.org
  - osv
  - pip
epss: 0.00126
epssPercentile: 0.0231
aliases:
  - GHSA-9w56-46f6-3qhx
ecosystem: pip
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-13T20:13:07.578455Z'
ingestedAt: '2026-10-13T16:35:46.735Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-102734)

Affected packages:

- `asteval < 1.0.9`

Patched in:

- `asteval 1.0.9`

Source: https://osv.dev/vulnerability/GHSA-9w56-46f6-3qhx