CVE-2026-49212Network attack vector

Read-only prop modification via cross-context HMAC replay

Published Jul 17, 2026 · Updated Jul 17, 2026

Insufficient authenticity verification in Symfony UX Live Component allows remote authenticated users to alter read-only component props. LiveComponentHydrator signs only sorted prop key/value pairs with one application secret, omitting the component name and the props or propsFromParent slot, so a valid blob can be replayed across contexts. Exploitation requires a signed blob from another component or slot with matching prop keys and changes application state without reported data disclosure or service interruption.

CVSS severity2.3
Low
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient authenticity verification in Symfony UX Live Component allows remote authenticated users to alter read-only component props. LiveComponentHydrator signs only sorted prop key/value pairs with one application secret, omitting the component name and the props or propsFromParent slot, so a valid blob can be replayed across contexts. Exploitation requires a signed blob from another component or slot with matching prop keys and changes application state without reported data disclosure or service interruption.

The record

CVE
CVE-2026-49212
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
Symfony
Product
Symfony UX
Classifications
CWE-345, T1565
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.36.0
  2. Affected versionversion=>= 3.0.0, < 3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Symfony · Symfony UXversion=< 2.36.0; version=>= 3.0.0, < 3.1.0

Published CVSS scores

2.3GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
T1565Data Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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