{"cve":"CVE-2026-106445","nvd":{"published":"2026-10-06T20:17:26.293","modified":"2026-10-12T15:17:06.910","status":"Awaiting Analysis","description":"Handlebars provides the power necessary to let users build semantic templates. From 3.0.0 until 4.7.10, Handlebars lookupProperty returns Function.prototype.constructor before applying the prototype-access deny list because constructor is an own property of Function.prototype. When an attacker can render a controlled template with allowProtoMethodsByDefault enabled and an accessible function in the template context, the template can traverse from that function through its prototype to Function.prototype and then obtain the Function constructor through the own-property bypass. This permits attacker-controlled JavaScript to execute with the server application's privileges. This issue is fixed in version 4.7.10.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","score":9.2},"cvss_v3":null,"cwes":["CWE-184","CWE-1289"],"references":["https://github.com/handlebars-lang/handlebars.js/commit/ceec388abe1d1aac8f6369860d5f390fa71ef4fa","https://github.com/handlebars-lang/handlebars.js/pull/2185","https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.10","https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-p8wg-vrv2-v86f","https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-p8wg-vrv2-v86f"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:58:01.639778232+00:00"},"epss":{"cve":"CVE-2026-106445","score":0.00589,"percentile":0.47861,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-p8wg-vrv2-v86f","url":"https://osv.dev/vulnerability/GHSA-p8wg-vrv2-v86f","summary":"Handlebars: JavaScript Injection via Own Property Check Bypass","modified":"2026-10-12T14:45:06.527043960Z","packages":[{"ecosystem":"npm","name":"handlebars","purl":"pkg:npm/handlebars","ranges":[">=3.0.0 <4.7.10"],"fixed":["4.7.10"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}