High severity · published Jul 17, 2026
CVE-2026-49212
Symfony UX: LiveComponentHydrator HMAC checksum lacks component and slot binding
7.5
CVSS
0.2%
EPSS
No
On KEV
Description
Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, the HMAC computed by Symfony\UX\LiveComponent\LiveComponentHydrator covered only sorted prop key/value pairs and did not include the component name, the slot identifier (props vs propsFromParent), or request context, allowing a signed blob minted for one component or slot to be replayed in another and set a read-only prop on a target component. This issue is fixed in versions 2.36.0 and 3.1.0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% 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; < 2.36.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49212
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49212
Patch
https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c
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-34w5-c283-j9fg
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