symfony/ux-live-component: Denial of service via unbounded batch action requests
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | symfony/ux-live-component | >= 2.5.0, < 2.36.0, >= 3.0.0, < 3.1.0 | 2.36.0, 3.1.0 |
References
- CVSS vector
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- Weakness (CWE)
CWE-770- Platform
- Composer
- Package
symfony/ux-live-component- Disclosed
- 19.06.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-mm82-c99c-h2cf - CC BY 4.0
Vulnerability history: symfony/ux-live-component
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 6
- First → latest
- 05.2025 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 3
- Low 3
Disclosures per year
- 2025: 1
- 2026: 5
-
symfony/ux-live-component: Denial of service via unbounded batch action requests this entry
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