CVE-2026-81887: Livewire/livewire Cross-Site Scripting Vulnerability
MODERATECVE-2026-81887 is a MODERATE cross-site scripting vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Livewire/livewire libraries in the Packagist ecosystem. The issue involves livewire dom-based cross-site scripting during client-side state handling. Remediation is available by upgrading affected packages to version 3.8.3, 4.3.4.
CVE-2026-81887 at a Glance
How to Fix CVE-2026-81887
To remediate this vulnerability, upgrade all affected Livewire/livewire dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade livewire/livewire to 3.8.3Upgrade livewire/livewire to 4.3.4Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for livewire/livewireHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-81887, inspect your project dependencies for Livewire/livewire:
inspect dependencies for livewire/livewireAnalyze the terminal output to locate any version of Livewire/livewire in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.8.3), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Livewire/livewire, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-81887 Affected Livewire/livewire Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
livewire/livewire
|
Packagist |
≥ 3.0.0-beta.1
< 3.8.3
|
3.8.3
|
|
livewire/livewire
|
Packagist |
≥ 4.0.0-beta.1
< 4.3.4
|
4.3.4
|
References
Frequently Asked Questions
What is CVE-2026-81887?
Which Livewire/livewire versions are affected?
What version fixes CVE-2026-81887?
Is livewire/livewire affected?
What CWE is associated with CVE-2026-81887?
How can I check Packagist dependencies for CVE-2026-81887?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-g3hc-697w-wm82",
"modified" : "2026-09-02T14:38:58Z",
"published" : "2026-09-02T14:38:58Z",
"aliases" : [ "CVE-2026-81887" ],
"summary" : "Livewire DOM-based cross-site scripting during client-side state handling",
"details" : "### Impact\nIn Livewire v3 (≤ 3.8.2) and v4 (≤ 4.3.3), a vulnerability allows unauthenticated attackers to execute arbitrary JavaScript in the origin of an affected application in specific scenarios. The issue stems from how certain client-side component state is handled. This vulnerability does not affect prior major versions. Exploitation requires user interaction, but does not require authentication or prior access to the application. The issue does not bypass server-side authorisation and grants an attacker no privileges beyond those the affected user already holds.\n\n### Patches\nThis issue has been patched in Livewire v3.8.3 and v4.3.4. All users are strongly encouraged to upgrade to these versions or later as soon as possible.\n\n### Workarounds\nThere is no known workaround at this time. Users are strongly advised to upgrade to a patched version immediately.",
"severity" : [ {
"type" : "CVSS_V4",
"score" : "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"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "livewire/livewire"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.0.0-beta.1"
}, {
"fixed" : "3.8.3"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 3.8.2"
}
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "livewire/livewire"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.0.0-beta.1"
}, {
"fixed" : "4.3.4"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.3.3"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/livewire/livewire/security/advisories/GHSA-g3hc-697w-wm82"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-81887"
}, {
"type" : "WEB",
"url" : "https://github.com/livewire/livewire/pull/10467"
}, {
"type" : "WEB",
"url" : "https://github.com/livewire/livewire/commit/11ebe646f7e81dde2d714815da8b3019d058561e"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/livewire/livewire"
}, {
"type" : "WEB",
"url" : "https://github.com/livewire/livewire/releases/tag/v3.8.3"
}, {
"type" : "WEB",
"url" : "https://github.com/livewire/livewire/releases/tag/v4.3.4"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-1321", "CWE-79" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-09-02T14:38:58Z",
"nvd_published_at" : "2026-08-31T21:17:52Z"
}
}