Symfony UX up to 2.35.x/3.0.x LiveComponent isLiveComponentRequest cross-domain policy

Summaryinfo

A vulnerability has been found in Symfony UX up to 2.35.x/3.0.x and classified as problematic. This affects the function isLiveComponentRequest of the component LiveComponent. The manipulation leads to cross-domain policy. This vulnerability is referenced as CVE-2026-49215. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Symfony UX up to 2.35.x/3.0.x. This issue affects the function isLiveComponentRequest of the component LiveComponent. The manipulation with an unknown input leads to a cross-domain policy vulnerability. Using CWE to declare the problem leads to CWE-942. The product uses a cross-domain policy file that includes domains that should not be trusted. Impacted is confidentiality. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-49215 since 05/28/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

Upgrading to version 2.36.0 or 3.1.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• Symfony

Name

• UX

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 3.0

License

• open-source

Website

• Product: https://github.com/symfony/ux/

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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