CVE-2026-33937Critical· 9.8▾ AbyssalPoC availableHandlebars 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 `NumberLitera…
▾ Abyssal zone — Critical with a public exploit or in-the-wild use
impact 53.9 · likelihood 0.4 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Public exploit / PoC code seen in 1 source. Availability, not in-the-wild use.
Exploit-prediction probability, daily snapshots since Aug 2.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
1.8%
1.8% → 2.3%
4 GitHub repos
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.
handlebars >= 4.0.0, < 4.7.9Upgrade past the affected range:
handlebars 4.7.9Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-33938High· 8.1Handlebars provides the power necessary to let users build semantic templates
CVE-2026-33940High· 8.1Handlebars provides the power necessary to let users build semantic templates
CVE-2026-33941High· 8.2Handlebars provides the power necessary to let users build semantic templates
CVE-2026-33939High· 7.5Handlebars provides the power necessary to let users build semantic templates
CVE-2021-23383Medium· 5.6The package handlebars before 4.7.7 are vulnerable to Prototype Pollution when selecting certain compiling options to compile templates coming from an untrusted source.
CVE-2026-106446Critical· 9.8Handlebars provides the power necessary to let users build semantic templates