{"cve":{"cve_id":"CVE-2026-33939","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00757,"epss_percentile":0.54232,"epss_as_of":"2026-10-15","description":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, when a Handlebars template contains decorator syntax referencing an unregistered decorator (e.g. `{{*n}}`), the compiled template calls `lookupProperty(decorators, \"n\")`, which returns `undefined`. The runtime then immediately invokes the result as a function, causing an unhandled `TypeError: ... is not a function` that crashes the Node.js process. Any application that compiles user-supplied templates without wrapping the call in a `try/catch` is vulnerable to a single-request Denial of Service. Version 4.7.9 fixes the issue. Some workarounds are available. Wrap compilation and rendering in `try/catch`. Validate template input before passing it to `compile()`; reject templates containing  decorator syntax (`{{*...}}`) if decorators are not used in your application. Use the pre-compilation workflow; compile templates at build time and serve only pre-compiled  templates; do not call `compile()` at request time.","published_at":"2026-03-27T21:08:24.664000Z","last_modified_at":"2026-09-04T13:19:26.173000Z","cvss_v3_score":7.5,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"poc","ssvc_automatable":true,"ssvc_technical_impact":"partial","cwes":["CWE-754","CWE-248"],"nvd_references":["https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-9cx6-37pm-9jff","https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2","https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"],"vuln_status":"Modified","trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-09-06T03:34:00.394538Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"N","value_label":"None"},{"metric":"I","name":"Integrity","value":"N","value_label":"None"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"handlebarsjs","vendor_name":"handlebarsjs","product_slug":"handlebars","product_name":"handlebars","version_start":"4.0.0","version_start_inclusive":true,"version_end":"4.7.9","version_end_inclusive":false,"cpe23_uri":"cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:*"},{"vendor_slug":"handlebars-lang","vendor_name":"handlebars-lang","product_slug":"handlebars.js","product_name":"handlebars.js","version_start":">= 4.0.0, < 4.7.9","version_start_inclusive":true,"version_end":">= 4.0.0, < 4.7.9","version_end_inclusive":true,"cpe23_uri":"cve5:handlebars-lang:handlebars.js:>= 4.0.0, < 4.7.9:>= 4.0.0, < 4.7.9"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-9cx6-37pm-9jff","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2026-03-27T21:08:24.664000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:53:20.032350Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:53:20.032350Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:53:20.032350Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"ssvc_changed","at":"2026-06-29T23:46:59.033383Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-29T23:46:59.033383Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-06-29T23:46:59.033383Z","label":"SSVC decision revised","source":"vulnrichment"}]}