{"id":"CVE-2026-33916","revision":"860f3d6b7d3c4953a0ab7fe40295abdc","records":[{"revision":"860f3d6b7d3c4953a0ab7fe40295abdc","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-33916","aliases":[],"title":"Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection","description":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `resolvePartial()` in the Handlebars runtime resolves partial names via a plain property lookup on `options.partials` without guarding against prototype-chain traversal. When `Object.prototype` has been polluted with a string value whose key matches a partial reference in a template, the polluted string is used as the partial body and rendered without HTML escaping, resulting in reflected or stored XSS. Version 4.7.9 fixes the issue. Some workarounds are available. Apply `Object.freeze(Object.prototype)` early in application startup to prevent prototype  pollution. Note: this may break other libraries, and/or use the Handlebars runtime-only build (`handlebars/runtime`), which does not compile templates  and reduces the attack surface.","state":0,"publishedAt":"2026-03-27T21:00:48.624+00:00","modifiedAt":"2026-03-30T15:41:36.977+00:00","affected":[{"ecosystem":"Vendor product","name":"handlebars.js","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"handlebars-lang\",\n                    \"product\": \"handlebars.js\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 4.0.0, < 4.7.9\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","score":4.7,"severity":"MEDIUM"}],"references":["https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2qvq-rjwj-gvw9","https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2","https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-33916","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-33916","identifiers":["CVE-2026-33916"]},"retained":false,"historicalAffected":[]}],"coverage":[]}