---
id: CVE-2026-77140
title: >-
  The extension validates the HMAC of a frontend employee edit link only in the
  action that renders the edit form, not in the action that persists the change
summary: >-
  The extension validates the HMAC of a frontend employee edit link only in the
  action that renders the edit form, not in the action that persists the change.
  An unauthenticated visitor who knows the UID of a visible employee record can
  se…
severity: none
cwe:
  - CWE-639
  - CWE-862
published: '2026-08-25'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T23:10:00.143'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77140'
references:
  - url: 'https://typo3.org/security/advisory/typo3-ext-sa-2026-018'
    label: f4fb688c-4412-4426-b4b8-421ecf27b14a
tags:
  - nvd
ingestedAt: '2026-09-28T23:23:00.542Z'
---

## Overview

The extension validates the HMAC of a frontend employee edit link only in the action that renders the edit form, not in the action that persists the change. An unauthenticated visitor who knows the UID of a visible employee record can send a direct POST request to the update action and overwrite that record without a valid edit link or any ownership check.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.