Answer in brief
CVE-2026-81887 records a Medium severity (CVSS 0.0) vulnerability in Livewire DOM-based cross-site scripting during client-side state handling. The current sources do not mark it as known exploited. The current feed maps livewire/livewire (composer), livewire/livewire (composer), livewire/livewire (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 0.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps livewire/livewire (composer), livewire/livewire (composer), livewire/livewire (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| livewire/livewirecomposer | >=3.0.0-beta.1,<=3.8.2 | 3.8.3 |
| livewire/livewirecomposer | >=4.0.0-beta.1,<=4.3.3 | 4.3.4 |
| livewire/livewiregeneric | >= 3.0.0-beta.1, < 3.8.3 || >= 4.0.0-beta.1, < 4.3.4 | Not reported |
Published upstream
Aug 31, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 31, 2026
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.
Quoted source text, attributed separately from HOL analysis.