---
id: CVE-2021-29047
title: >-
  The SimpleCaptcha implementation in Liferay Portal 7.3.4, 7.3.5 and Liferay
  DXP 7.3 before fix pack 1 does not invalidate CAPTCHA answers after it is
  used, which allows remote attackers to repeatedly perform actions protected by
  a CAPTCH…
summary: >-
  The SimpleCaptcha implementation in Liferay Portal 7.3.4, 7.3.5 and Liferay
  DXP 7.3 before fix pack 1 does not invalidate CAPTCHA answers after it is
  used, which allows remote attackers to repeatedly perform actions protected by
  a CAPTCH…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-287
vendor: liferay
product: dxp
affected:
  - dxp < 7.3
  - dxp = 7.3
  - liferay_portal = 7.3.4
  - liferay_portal = 7.3.5
patched:
  - dxp 7.3
published: '2021-05-16'
updated: '2026-07-05'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-29047'
references:
  - url: >-
      https://portal.liferay.dev/learn/security/known-vulnerabilities/-/asset_publisher/HbL5mxmVrnXW/content/id/120743467
    label: cve@mitre.org
  - url: 'http://liferay.com'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://portal.liferay.dev/learn/security/known-vulnerabilities/-/asset_publisher/HbL5mxmVrnXW/content/id/120743467
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01065
epssPercentile: 0.63179
ingestedAt: '2026-07-05T02:00:01.596Z'
---

## Overview

The SimpleCaptcha implementation in Liferay Portal 7.3.4, 7.3.5 and Liferay DXP 7.3 before fix pack 1 does not invalidate CAPTCHA answers after it is used, which allows remote attackers to repeatedly perform actions protected by a CAPTCHA challenge by reusing the same CAPTCHA answer.

## Affected

- `dxp < 7.3`
- `dxp = 7.3`
- `liferay_portal = 7.3.4`
- `liferay_portal = 7.3.5`

## Remediation

Upgrade past the affected range:

- `dxp 7.3`