{"id":"CVE-2026-106445","title":"Handlebars provides the power necessary to let users build semantic templates","summary":"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 i…","severity":"critical","cvss":9.2,"cvssVector":"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","cwe":["CWE-184","CWE-1289"],"vendor":"handlebars-lang","product":"handlebars.js","affected":["handlebars.js >= 4.0.0, < 4.7.10"],"patched":["handlebars 4.7.10"],"published":"2026-10-06","updated":"2026-10-12","sourceUpdated":"2026-10-12T15:17:06.910","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-106445","references":[{"url":"https://github.com/handlebars-lang/handlebars.js/commit/ceec388abe1d1aac8f6369860d5f390fa71ef4fa","label":"security-advisories@github.com"},{"url":"https://github.com/handlebars-lang/handlebars.js/pull/2185","label":"security-advisories@github.com"},{"url":"https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.10","label":"security-advisories@github.com"},{"url":"https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-p8wg-vrv2-v86f","label":"security-advisories@github.com"},{"url":"https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-p8wg-vrv2-v86f","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-106445"},{"url":"https://github.com/advisories/GHSA-p8wg-vrv2-v86f"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-106445.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-106445"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2547112"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-106445"}],"tags":["nvd","exploit-available","cve.org","ghsa","npm","csaf","vex","red-hat"],"epss":0.00589,"epssPercentile":0.47947,"exploits":{"github":1,"githubRepos":["https://github.com/murrez/CVE-2026-106445"],"checkedAt":"2026-10-27T16:55:04.792Z"},"exploitAvailable":true,"aliases":["GHSA-p8wg-vrv2-v86f"],"ecosystem":"npm","cvssSource":"cna","scores":{"cna":9.2,"vendor":8.1},"ingestedAt":"2026-10-06T20:16:42.486Z","ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-09T01:42:53.531967Z"},"slug":"CVE-2026-106445","body":"## Overview\n\nHandlebars 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-106445)\n\nAffected packages:\n\n- `handlebars >= 4.0.0, <= 4.7.9`\n\nPatched in:\n\n- `handlebars 4.7.10`\n\nSource: https://github.com/advisories/GHSA-p8wg-vrv2-v86f\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Cryostat 4, Multicluster Engine for Kubernetes, Node HealthCheck Operator, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat AMQ Broker 7, Red Hat build of Apache Camel for Spring Boot 4, … · no fix planned: Cryostat 4, Multicluster Engine for Kubernetes, Node HealthCheck Operator, Red Hat Advanced Cluster Management for Kubernetes 2, … · updated 2026-10-13 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-106445.json)","depth":"abyssal","depthScore":63,"depthScoreParts":{"impact":50.6,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":219348,"id":"CVE-2026-106445","ts":1791806285214,"field":"exploit_available","old":"false","new":"true"}]}