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Vulnerability · Published Aug 31, 2026 · Assigned by GitHub_M

CVE-2026-81887Livewire DOM-based cross-site scripting during client-side state handling

Medium 5.1

In plain English

A medium-severity cross-site scripting in livewire from livewire. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.1Medium
Exploit odds (30 days)0.7%top 47.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Livewire is a full-stack framework for Laravel. From 3.0.0-beta.1 until 3.8.3 and 4.3.4, the dot-notated query-string parser in js/plugins/history/index.js, including fromQueryString() and insertDotNotatedValueIntoData(), accepts the __proto__, constructor, and prototype path segments and creates inherited objects. Client-side state handlers then access effects.html, effects.js, effects.xjs, and effects.scripts without Object.prototype.hasOwnProperty.call(), allowing inherited attacker-controlled state to be treated as trusted effects. An unauthenticated attacker can craft a URL that, when opened by a user, executes arbitrary JavaScript in the affected application's origin. Exploitation requires user interaction and does not bypass server-side authorization or grant privileges beyond the affected user. This issue is fixed in versions 3.8.3 and 4.3.4.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Packagistlivewire/livewire3.8.3GHSA-g3hc-697w-wm82
Packagistlivewire/livewire4.3.4GHSA-g3hc-697w-wm82

Affected products (as reported)

VendorProductVersions
livewire livewire >= 3.0.0-beta.1, < 3.8.3>= 4.0.0-beta.1, < 4.3.4

Weakness: CWE-79, CWE-1321 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References