{"id":"EUVD-2026-16847","revision":null,"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":[]},{"revision":"06836d8dd5254923af51ed54048b2788","observedAt":"2026-11-01T06:04:56.629+00:00","statement":{"source":"euvd","id":"EUVD-2026-16847","aliases":["CVE-2026-33916","GHSA-2qvq-rjwj-gvw9"],"title":"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 gu…","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":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD 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":null}],"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://euvd.enisa.europa.eu/vulnerability/EUVD-2026-16847","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Mar 27, 2026, 9:00:48 PM","dateUpdated":"Mar 30, 2026, 3:41:36 PM"},"relatedAdvisories":[{"id":"WID-SEC-W-2026-3046","title":"IBM Concert: Mehrere Schwachstellen","vulnerabilityIds":["CVE-2019-19921","CVE-2021-23337","CVE-2024-3651","CVE-2024-39338","CVE-2024-45590","CVE-2025-13465","CVE-2025-15284","CVE-2025-15599","CVE-2025-22874","CVE-2025-47273","CVE-2025-47907","CVE-2025-52881","CVE-2025-53643","CVE-2025-55184","CVE-2025-58056","CVE-2025-58188","CVE-2025-58189","CVE-2025-61723","CVE-2025-61730","CVE-2025-64649","CVE-2025-64756","CVE-2025-67221","CVE-2025-68121","CVE-2025-68146","CVE-2026-0540","CVE-2026-2327","CVE-2026-23490","CVE-2026-23897","CVE-2026-2391","CVE-2026-23949","CVE-2026-24486","CVE-2026-25528","CVE-2026-25547","CVE-2026-25639","CVE-2026-25990","CVE-2026-26007","CVE-2026-26019","CVE-2026-26996","CVE-2026-27142","CVE-2026-27212","CVE-2026-27699","CVE-2026-27903","CVE-2026-27904","CVE-2026-28684","CVE-2026-29063","CVE-2026-29181","CVE-2026-2950","CVE-2026-31808","CVE-2026-31900","CVE-2026-32274","CVE-2026-32288","CVE-2026-32597","CVE-2026-32630","CVE-2026-32887","CVE-2026-32952","CVE-2026-33186","CVE-2026-33532","CVE-2026-33750","CVE-2026-33814","CVE-2026-33816","CVE-2026-33916","CVE-2026-34043","CVE-2026-34073","CVE-2026-34077","CVE-2026-3520","CVE-2026-35469","CVE-2026-35515","CVE-2026-3627","CVE-2026-39823","CVE-2026-39825","CVE-2026-39826","CVE-2026-39892","CVE-2026-39984","CVE-2026-40175","CVE-2026-40179","CVE-2026-40181","CVE-2026-40190","CVE-2026-40347","CVE-2026-41066","CVE-2026-41182","CVE-2026-41238","CVE-2026-41239","CVE-2026-41240","CVE-2026-41305","CVE-2026-41324","CVE-2026-41425","CVE-2026-41481","CVE-2026-41488","CVE-2026-41602","CVE-2026-41636","CVE-2026-42151","CVE-2026-42154","CVE-2026-42198","CVE-2026-42211","CVE-2026-42338","CVE-2026-42342","CVE-2026-42561","CVE-2026-42577","CVE-2026-43870","CVE-2026-44405","CVE-2026-44431","CVE-2026-44432","CVE-2026-44486","CVE-2026-44487","CVE-2026-44488","CVE-2026-44492","CVE-2026-44494","CVE-2026-44496","CVE-2026-44728","CVE-2026-4539","CVE-2026-45409","CVE-2026-45736","CVE-2026-46625","CVE-2026-4800","CVE-2026-4923","CVE-2026-4926","CVE-2026-7246","CVE-2026-8723"]},{"id":"WID-SEC-W-2026-1407","title":"IBM App Connect Enterprise Certified Container: Mehrere Schwachstellen","vulnerabilityIds":["CVE-2026-26013","CVE-2026-27142","CVE-2026-28277","CVE-2026-28684","CVE-2026-32288","CVE-2026-33151","CVE-2026-33349","CVE-2026-33532","CVE-2026-33891","CVE-2026-33894","CVE-2026-33895","CVE-2026-33896","CVE-2026-33916","CVE-2026-34601","CVE-2026-35469","CVE-2026-39406","CVE-2026-39407","CVE-2026-39408","CVE-2026-39409","CVE-2026-39410","CVE-2026-39983","CVE-2026-40175","CVE-2026-40347","CVE-2026-40895","CVE-2026-41238","CVE-2026-41239","CVE-2026-41240","CVE-2026-4923","CVE-2026-4926"]},{"id":"msrc_CVE-2026-33916","title":"Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection","vulnerabilityIds":["CVE-2026-33916"]}],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-16847","identifiers":["EUVD-2026-16847","CVE-2026-33916","GHSA-2qvq-rjwj-gvw9"]},"retained":false,"historicalAffected":[]},{"revision":"25879df150f34a29aca8c0f1e7ffbae0","observedAt":"2026-10-27T09:03:00.507+00:00","statement":{"source":"nvd","id":"CVE-2026-33916","aliases":[],"title":"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 gu…","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":"2026-03-27T21:17:27.237+00:00","modifiedAt":"2026-10-26T22:10:00.163+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","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"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","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/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2","https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9","https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2qvq-rjwj-gvw9"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-33916","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-79","CWE-1321"],"productCriteria":["cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:*"],"sourceDates":{"published":"2026-03-27T21:17:27.237","lastModified":"2026-10-26T22:10:00.163"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-33916","identifiers":["CVE-2026-33916"]},"retained":false,"historicalAffected":[]},{"revision":"e51da863c38e48fc9b1f94dfc308d3af","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-2qvq-rjwj-gvw9","aliases":["CVE-2026-33916"],"title":"Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection","description":"## Summary\n\n`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.\n\n## Description\n\nThe root cause is in `lib/handlebars/runtime.js` inside `resolvePartial()` and `invokePartial()`:\n\n```javascript\n// Vulnerable: plain bracket access traverses Object.prototype\npartial = options.partials[options.name];\n```\n\n`hasOwnProperty` is never checked, so if `Object.prototype` has been seeded with a key whose name matches a partial reference in the template (e.g. `widget`), the lookup succeeds and the polluted string is returned. The runtime emits a prototype-access warning, but the partial is still resolved and its content is inserted into the rendered output unescaped. This contradicts the documented security model and is distinct from CVE-2021-23369 and CVE-2021-23383, which addressed data property access rather than partial template resolution.\n\n**Prerequisites for exploitation:**\n1. The target application must be vulnerable to prototype pollution (e.g. via `qs`, `minimist`, or\n any querystring/JSON merge sink).\n2. The attacker must know or guess the name of a partial reference used in a template.\n\n## Proof of Concept\n\n```javascript\nconst Handlebars = require('handlebars');\n\n// Step 1: Prototype pollution (via qs, minimist, or another vector)\nObject.prototype.widget = '
';\n\n// Step 2: Normal template that references a partial\nconst template = Handlebars.compile('Welcome! {{> widget}}
');\n\n// Step 3: Render — XSS payload injected unescaped\nconst output = template({});\n// Output: Welcome!