Medium severity · published Jul 17, 2026
CVE-2026-49209
Symfony UX: Denial of service in symfony/ux-live-component via unbounded batch action requests
6.5
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
UX
ux · symfony
>= 3.0.0, < 3.1.0; >= 2.5.0, < 2.36.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49209
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49209
Patch
https://github.com/symfony/ux/commit/95e878d5257f13d6d652ca95e3ef6bb0934d674f
Release Notes
https://github.com/symfony/ux/releases/tag/v2.36.0
Release Notes
https://github.com/symfony/ux/releases/tag/v3.1.0
Vendor Advisory
https://github.com/symfony/ux/security/advisories/GHSA-mm82-c99c-h2cf
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