{"id":"CVE-2026-81887","title":"Livewire is a full-stack framework for Laravel","summary":"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 __p…","severity":"medium","cwe":["CWE-79","CWE-1321"],"vendor":"livewire","product":"livewire/livewire","affected":["livewire/livewire >= 3.0.0-beta.1, <= 3.8.2","livewire/livewire >= 4.0.0-beta.1, <= 4.3.3"],"patched":["livewire/livewire 3.8.3","livewire/livewire 4.3.4"],"published":"2026-08-31","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:09:13.080","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81887","references":[{"url":"https://github.com/livewire/livewire/commit/11ebe646f7e81dde2d714815da8b3019d058561e","label":"security-advisories@github.com"},{"url":"https://github.com/livewire/livewire/pull/10467","label":"security-advisories@github.com"},{"url":"https://github.com/livewire/livewire/releases/tag/v3.8.3","label":"security-advisories@github.com"},{"url":"https://github.com/livewire/livewire/releases/tag/v4.3.4","label":"security-advisories@github.com"},{"url":"https://github.com/livewire/livewire/security/advisories/GHSA-g3hc-697w-wm82","label":"security-advisories@github.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81887"},{"url":"https://github.com/advisories/GHSA-g3hc-697w-wm82"}],"tags":["nvd","ghsa","composer"],"epss":0.005,"epssPercentile":0.4186,"aliases":["GHSA-g3hc-697w-wm82"],"ecosystem":"composer","ingestedAt":"2026-09-02T14:45:29.884Z","slug":"CVE-2026-81887","body":"## Overview\n\nLivewire 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-81887)\n\nAffected packages:\n\n- `livewire/livewire >= 3.0.0-beta.1, <= 3.8.2`\n- `livewire/livewire >= 4.0.0-beta.1, <= 4.3.3`\n\nPatched in:\n\n- `livewire/livewire 3.8.3`\n- `livewire/livewire 4.3.4`\n\nSource: https://github.com/advisories/GHSA-g3hc-697w-wm82","depth":"sunlit","depthScore":28,"depthScoreParts":{"impact":27.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}