What’s Vulnerable › Vulnerabilities

CVE-2026-102734: asteval sandbox escape: arbitrary native memory read/write via numpy ctypes in default asteval Interpreter

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-13 · updated 2026-10-16
• Weakness: CWE-693

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

• lmfit asteval: before 1.0.9

References

• https://github.com/lmfit/asteval/commit/a3e56e7f8ed567a4817684d94213b290359077b4
• https://github.com/lmfit/asteval/pull/153
• https://github.com/lmfit/asteval/releases/tag/1.0.9
• https://github.com/lmfit/asteval/security/advisories/GHSA-9w56-46f6-3qhx

Get alerted when CVE-2026-102734 or the next vulnerability affects your stack