---
id: CVE-2026-74890
aliases:
  - PYSEC-2026-3766
  - GHSA-rvc2-5jxq-gpcj
title: >-
  openssl_encrypt versions before 1.4.0 contain an authentication bypass
  vulnerability in CamelliaCipher that disables HMAC tag generation …
summary: >-
  openssl_encrypt versions before 1.4.0 contain an authentication bypass
  vulnerability in CamelliaCipher that disables HMAC tag generation and
  verification when the PYTEST_CURRENT_TEST environment variable is set.
  Attackers with code execu…
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: '2026-09-02'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/PYSEC-2026-3766'
references:
  - url: >-
      https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-rvc2-5jxq-gpcj
  - url: >-
      https://www.vulncheck.com/advisories/openssl-encrypt-before-hmac-authentication-bypass-via-environment-variable
tags:
  - osv
  - pip
epss: 0.00213
epssPercentile: 0.10296
ingestedAt: '2026-09-02T19:31:25.660Z'
---

## Overview

openssl_encrypt versions before 1.4.0 contain an authentication bypass vulnerability in CamelliaCipher that disables HMAC tag generation and verification when the PYTEST_CURRENT_TEST environment variable is set. Attackers with code execution can set this environment variable to produce unauthenticated ciphertext and bypass integrity protection on encrypted data.

## Affected packages

- `openssl-encrypt < 1.4.0`

## Remediation

Upgrade to a patched release:

- `openssl-encrypt 1.4.0`