CVE-2026-49209Network attack vector

Service interruption via unbounded batch action requests

Published Jul 17, 2026 · Updated Jul 17, 2026

Resource exhaustion in Symfony UX Live Component allows remote authenticated users to interrupt application service via a crafted batch request. BatchActionController::__invoke() iterates over the client-supplied actions array and launches a full HttpKernel sub-request for every entry without enforcing a size limit. Authentication to an application's Live Component endpoint is required; a single oversized request exhausts CPU, memory, and database connections.

CVSS severity5.3
Medium
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Symfony UX Live Component allows remote authenticated users to interrupt application service via a crafted batch request. BatchActionController::__invoke() iterates over the client-supplied actions array and launches a full HttpKernel sub-request for every entry without enforcing a size limit. Authentication to an application's Live Component endpoint is required; a single oversized request exhausts CPU, memory, and database connections.

The record

CVE
CVE-2026-49209
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
Symfony
Product
Symfony UX
Classifications
CWE-770, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.5.0, < 2.36.0
  2. Affected versionversion=>= 3.0.0, < 3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Symfony · Symfony UXversion=>= 2.5.0, < 2.36.0; version=>= 3.0.0, < 3.1.0

Published CVSS scores

5.3GitHub CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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