Symfony UX is a JavaScript ecosystem for Symfony. From 2.22.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\EventListener\LiveComponentSubscriber::isLiveComponentRequest() gates #[LiveAction] invocations on Accept: application/vnd.live-component+html, but the Accept header is CORS-safelisted and cross-origin fetch() can set it without preflight, allowing forged cross-origin #[LiveAction] requests against a victim session when applications use SameSite=None, credentials: 'include', a permissive cookie policy, or a same-origin pivot. This issue is fixed in versions 2.36.0 and 3.1.0.
CVE-2026-49215
MEDIUMNVD 5.45.4—Trending — 4 sources updated this week
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 5.4 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 98% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.4
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.4Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.4
- EG Score
- 5.4(medium)
- EG Risk
- 24(Track)EG Risk 24/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity54% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 2.0%
- KEV
- Not listed
Published
June 19, 2026
Last Modified
July 20, 2026
References (4)
- security-advisories@githubhttps://github.com/symfony/ux/commit/aed7493db2b4b7bf1f9c79b33cda544f06904b27
- security-advisories@githubhttps://github.com/symfony/ux/releases/tag/v2.36.0
- security-advisories@githubhttps://github.com/symfony/ux/releases/tag/v3.1.0
- security-advisories@githubhttps://github.com/symfony/ux/security/advisories/GHSA-4m4j-hmqq-3gxm
Vendor Advisories for CVE-2026-49215(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
Packagist(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| symfony/ux-live-component | v3.0.0 | 3.1.0 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 10× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-23 03:18 UTCEG score recompute▲ 3.30
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-20 17:06 UTCNVD updateCVSS v3 → 5.4 · severity → MEDIUM
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-17 16:20 UTCEG score recompute▲ 2.10
- 2026-07-17 16:19 UTCMITRE cvelistV5CVSS v3 → 2.1 · CVSS v4 → 2.1
- 2026-06-19 19:36 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-49215?
CVE-2026-49215 is a medium vulnerability published on June 19, 2026. Symfony UX is a JavaScript ecosystem for Symfony. From 2.22.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\EventListener\LiveComponentSubscriber::isLiveComponentRequest() gates #[LiveAction] invocations on Accept: application/vnd.live-component+html, but the Accept header is CORS-safelisted and…
When was CVE-2026-49215 disclosed?
CVE-2026-49215 was first published in the National Vulnerability Database on June 19, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49215 actively exploited?
CVE-2026-49215 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-49215?
CVE-2026-49215 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-49215?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49215, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49215
Is Your Infrastructure Affected by CVE-2026-49215?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.