CVE-2026-32640

CriticalRCE

Published: 16 March 2026

Published

16 March 2026

Modified

21 April 2026

KEV Added

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Patch

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CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0005 15.4th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-32640 is a critical-severity Code Injection (CWE-94) vulnerability in Danthedeckie Simpleeval. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 15.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and CM-7 (Least Functionality).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Directly mitigates the CVE by requiring timely remediation of the sandbox leakage flaw through upgrading SimpleEval to the patched version 1.0.5.

SI-10 Information Input Validation partial match

prevent

Addresses improper control of dynamically-determined object attributes by validating and sanitizing inputs to the expression evaluator, reducing risk of smuggling dangerous callbacks or objects.

CM-7 Least Functionality partial match

prevent

Enforces least functionality by restricting the SimpleEval sandbox to only approved objects and modules, preventing leakage of dangerous attributes.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1059.006 Python Execution

Adversaries may abuse Python commands and scripts for execution.

attack.mitre.org →

Why these techniques?

Remote unauthenticated RCE via sandbox escape in Python library enables exploitation of public-facing applications (T1190) and abuse of Python interpreter (T1059.006).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

SimpleEval is a library for adding evaluatable expressions into python projects. Prior to 1.0.5, objects (including modules) can leak dangerous modules through to direct access inside the sandbox. If the objects you've passed in as names to SimpleEval have modules…

or other disallowed / dangerous objects available as attrs. Additionally, dangerous functions or modules could be accessed by passing them as callbacks to other safe functions to call. The latest version 1.0.5 has this issue fixed. This vulnerability is fixed in 1.0.5.

Deeper analysisAI

CVE-2026-32640 affects SimpleEval, a Python library designed for safely evaluating expressions in projects. Prior to version 1.0.5, the library's sandboxing mechanism fails to prevent leakage of dangerous modules or objects. This occurs when user-provided objects passed as names to SimpleEval expose disallowed modules or attributes directly within the sandbox, or when dangerous functions/modules are smuggled in as callbacks to otherwise safe functions. The issue is associated with CWE-94 (Improper Control of Generation of Code) and CWE-915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes), earning a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Remote attackers require no privileges or user interaction to exploit this vulnerability over a network with low complexity. By crafting malicious expressions that leverage the leaked objects or callbacks, they can bypass sandbox restrictions and access prohibited modules or functions, potentially leading to arbitrary code execution, data exfiltration, or system compromise on the host running the vulnerable SimpleEval instance.

The vulnerability is fully addressed in SimpleEval version 1.0.5, which patches the sandbox leakage issues. Official advisories, including the GitHub security advisory at GHSA-44vg-5wv2-h2hg and a Debian LTS announcement, recommend immediate upgrading to the fixed version for all affected deployments.