Vulnerability · Published Jul 17, 2026 · Assigned by GitHub_M

CVE-2026-49209Symfony UX: Denial of service in symfony/ux-live-component via unbounded batch action requests

Medium 5.3

In plain English

A medium-severity resource allocation without limits in ux from symfony. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.6%top 53.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Symfony UX is a JavaScript ecosystem for Symfony. From 2.5.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\Controller\BatchActionController::__invoke() iterates over the client-supplied actions array and issues a full HttpKernel sub-request for each entry; because the array size is never bounded, an authenticated client can submit a single _batch request containing thousands of actions and exhaust CPU, memory, and database connections on the application server. This issue is fixed in versions 2.36.0 and 3.1.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	symfony/ux-live-component	2.36.0	GHSA-mm82-c99c-h2cf
Packagist	symfony/ux-live-component	3.1.0	GHSA-mm82-c99c-h2cf

Affected products (as reported)

Vendor	Product	Versions
symfony	ux	>= 3.0.0, < 3.1.0>= 2.5.0, < 2.36.0

Weakness: CWE-770 · 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

References

https://github.com/symfony/ux/security/advisories/GHSA-mm82-c99c-h2cf x_refsource_CONFIRM
https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f x_refsource_MISC
https://github.com/symfony/ux/releases/tag/v2.36.0 x_refsource_MISC
https://github.com/symfony/ux/releases/tag/v3.1.0 x_refsource_MISC