---
id: CVE-2026-74871
title: >-
  openssl_encrypt versions before 1.4.6 contain a key derivation flaw in
  sequential XOR composition mode where the last stage cancels out during key
  generation
summary: >-
  openssl_encrypt versions before 1.4.6 contain a key derivation flaw in
  sequential XOR composition mode where the last stage cancels out during key
  generation. When configured with a single KDF and no prior hashing stage,
  attackers can by…
severity: medium
cvss: 6.2
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-916
vendor: jahlives
product: openssl_encrypt
affected:
  - openssl_encrypt < 1.4.6
patched:
  - openssl_encrypt 1.4.6
published: '2026-08-17'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T16:56:31.877'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74871'
references:
  - url: >-
      https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-vxf9-vwp6-2w43
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/openssl-encrypt-before-kdf-bypass-via-sequential-xor
    label: disclosure@vulncheck.com
tags:
  - nvd
  - osv
  - pip
epss: 0.00108
epssPercentile: 0.0108
ingestedAt: '2026-09-08T21:11:12.279Z'
aliases:
  - PYSEC-2026-3976
  - GHSA-vxf9-vwp6-2w43
ecosystem: pip
scores:
  nvd: 6.2
  osv: 5.5
---

## Overview

openssl_encrypt versions before 1.4.6 contain a key derivation flaw in sequential XOR composition mode where the last stage cancels out during key generation. When configured with a single KDF and no prior hashing stage, attackers can bypass memory-hard key derivation and perform offline password cracking at SHA-256 speed instead of the configured KDF cost.

## Affected

- `openssl_encrypt < 1.4.6`

## Remediation

Upgrade past the affected range:

- `openssl_encrypt 1.4.6`

## Package advisory (CVE-2026-74871)

Affected packages:

- `openssl-encrypt < 1.4.6`

Patched in:

- `openssl-encrypt 1.4.6`

Source: https://osv.dev/vulnerability/PYSEC-2026-3976