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CVE-2026-49212

HIGHCVSS 7.5/10EPSS 0.18%

Last modified

CVE-2026-49212 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.18% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS 4.0
6.9/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.18%

7.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
SymfonyUx>= 2.8.0, < 2.36.0
SymfonyUx3.0.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-49212?
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.
How severe is CVE-2026-49212?
CVE-2026-49212 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2026-49212?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST