---
id: CVE-2026-81721
aliases:
  - PYSEC-2026-3803
  - GHSA-7894-5gw8-69hr
title: >-
  openssl_encrypt before 1.4.9 fails to validate KDF cost parameters in
  encrypted file metadata and keystore headers, allowing attackers to…
summary: >-
  openssl_encrypt before 1.4.9 fails to validate KDF cost parameters in
  encrypted file metadata and keystore headers, allowing attackers to trigger
  unbounded memory allocation. Attackers can craft malicious encrypted files
  declaring arbitr…
severity: none
vendor: openssl-encrypt
product: openssl-encrypt
ecosystem: pip
affected:
  - openssl-encrypt < 1.4.9
patched:
  - openssl-encrypt 1.4.9
published: '2026-08-27'
updated: '2026-09-03'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/PYSEC-2026-3803'
references:
  - url: >-
      https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-7894-5gw8-69hr
  - url: >-
      https://www.vulncheck.com/advisories/openssl-encrypt-before-1.4.9-denial-of-service-via-kdf-2
tags:
  - osv
  - pip
epss: 0.00581
epssPercentile: 0.45435
ingestedAt: '2026-09-03T19:32:12.490Z'
---

## Overview

openssl_encrypt before 1.4.9 fails to validate KDF cost parameters in encrypted file metadata and keystore headers, allowing attackers to trigger unbounded memory allocation. Attackers can craft malicious encrypted files declaring arbitrarily large Argon2, scrypt, or balloon KDF parameters to exhaust system memory and crash the process without authentication.

## Affected packages

- `openssl-encrypt < 1.4.9`

## Remediation

Upgrade to a patched release:

- `openssl-encrypt 1.4.9`