---
id: CVE-2026-74899
aliases:
  - PYSEC-2026-3727
title: >-
  openssl_encrypt versions before 1.4.0 contain a sandbox escape vulnerability
  in IsolatedPluginExecutor that exposes Python type objects i…
summary: >-
  openssl_encrypt versions before 1.4.0 contain a sandbox escape vulnerability
  in IsolatedPluginExecutor that exposes Python type objects in restricted
  exec() builtins. Attackers can traverse the Python class hierarchy via
  __class__.__mro_…
severity: none
vendor: openssl-encrypt
product: openssl-encrypt
ecosystem: pip
affected:
  - openssl-encrypt < 1.4.0
patched:
  - openssl-encrypt 1.4.0
published: '2026-08-17'
updated: '2026-08-29'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/PYSEC-2026-3727'
references:
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-43jx-gxq4-jpjc
  - url: >-
      https://www.vulncheck.com/advisories/openssl-encrypt-before-sandbox-escape-via-type-hierarchy
  - url: >-
      https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-m25m-ggxg-239c
tags:
  - osv
  - pip
epss: 0.0075
epssPercentile: 0.53008
ingestedAt: '2026-08-29T19:29:14.910Z'
---

## Overview

openssl_encrypt versions before 1.4.0 contain a sandbox escape vulnerability in IsolatedPluginExecutor that exposes Python type objects in restricted exec() builtins. Attackers can traverse the Python class hierarchy via __class__.__mro__.__subclasses__() to access system functions and execute arbitrary OS commands.

## Affected packages

- `openssl-encrypt < 1.4.0`

## Remediation

Upgrade to a patched release:

- `openssl-encrypt 1.4.0`