---
id: CVE-2026-49209
title: >-
  symfony/ux-live-component: Denial of service via unbounded batch action
  requests
summary: >-
  symfony/ux-live-component: Denial of service via unbounded batch action
  requests
severity: low
cwe:
  - CWE-770
vendor: symfony
product: symfony/ux-live-component
affected:
  - 'symfony/ux-live-component >= 2.5.0, < 2.36.0'
  - 'symfony/ux-live-component >= 3.0.0, < 3.1.0'
patched:
  - symfony/ux-live-component 2.36.0
  - symfony/ux-live-component 3.1.0
published: '2026-06-19'
updated: '2026-06-19'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-mm82-c99c-h2cf'
references:
  - url: 'https://github.com/symfony/ux/security/advisories/GHSA-mm82-c99c-h2cf'
  - url: >-
      https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f
  - url: >-
      https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49209.yaml
  - url: 'https://github.com/advisories/GHSA-mm82-c99c-h2cf'
tags:
  - ghsa
  - composer
ingestedAt: '2026-06-22T15:52:21.067Z'
ecosystem: composer
epss: 0.0056
epssPercentile: 0.44216
---

## Overview

### Description

`Symfony\UX\LiveComponent\Controller\BatchActionController::__invoke()` iterates over the client-supplied `actions` array and issues a full `HttpKernel` sub-request for each entry (event subscribers, validators, Doctrine, rendering). The array size is never bounded, so an authenticated client can submit a single `_batch` request containing thousands of actions and exhaust CPU, memory, and database connections on the application server.

### Resolution

`BatchActionController` now enforces an upper bound of 50 actions per `_batch` request (`MAX_ACTIONS_PER_BATCH`) and rejects larger payloads up front with a `BadRequestHttpException`. The matching JavaScript backend was also updated to split larger client-side batches into multiple requests so legitimate usage isn't affected.

The patch for this issue is available [here](https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f) for branch 2.x (and forward-ported to 3.x).

### Credits

Symfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.

## Affected packages

- `symfony/ux-live-component >= 2.5.0, < 2.36.0`
- `symfony/ux-live-component >= 3.0.0, < 3.1.0`

## Remediation

Upgrade to a patched release:

- `symfony/ux-live-component 2.36.0`
- `symfony/ux-live-component 3.1.0`