Vulnerability in symfony/ux-live-component (CVE-2026-49209)
Summary
Vulnerability in symfony/ux-live-component (CVE-2026-49209). Risk of unauthorized operations or information disclosure. Exploitable via actions. Mitigation: upgrade to 3.1.0 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-49209 has been found in symfony/ux-live-component.
Attackers can target a specific entry point like actions over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade symfony/ux-live-component to 3.1.0 or later.
If unsure, ask your IT team or search "symfony/ux-live-component CVE-2026-49209" on the vendor's site.
CVE-2026-49209 (symfony/ux-live-component) — CWE-770 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: actions / HttpKernel / _batch / BatchActionController
Patched: 3.1.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-770) exists in symfony/ux-live-component. Attackers reach the vulnerable code path via actions.
Check the vendor advisory for the affected versions of symfony/ux-live-component. Attack surface: actions / HttpKernel / _batch / BatchActionController.
Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.
Update to 3.1.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'symfony/ux-live-component' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'symfony/ux-live-component' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
symfony/ux-live-componentを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade symfony/ux-live-component to 3.1.0ステージング環境で 3.1.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web security-advisories@github.com
- web security-advisories@github.com