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GHSA-MM82-C99C-H2CF

Vulnerability from github – Published: 2026-06-19 19:34 – Updated: 2026-06-19 19:34
VLAI
Summary
symfony/ux-live-component: Denial of service via unbounded batch action requests
Details

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 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.

Severity
1.3 (Low)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/ux-live-component"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.5.0"
            },
            {
              "fixed": "2.36.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "symfony/ux-live-component"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49209"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T19:34:45Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Description\n\n`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.\n\n### Resolution\n\n`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\u0027t affected.\n\nThe patch for this issue is available [here](https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f) for branch 2.x (and forward-ported to 3.x).\n\n### Credits\n\nSymfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.",
  "id": "GHSA-mm82-c99c-h2cf",
  "modified": "2026-06-19T19:34:45Z",
  "published": "2026-06-19T19:34:45Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/symfony/ux/security/advisories/GHSA-mm82-c99c-h2cf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-live-component/CVE-2026-49209.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/symfony/ux"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "symfony/ux-live-component: Denial of service via unbounded batch action requests"
}



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