hbs vulnerable to Denial of Service via unhandled exception in async helper output escaping
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Hbs | Hbs |
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No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.412% probability within 30 days)
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| First Time appeared |
Hbs
Hbs hbs |
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| Vendors & Products |
Hbs
Hbs hbs |
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| Metrics |
ssvc
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| Description | hbs is an Express view engine wrapper for Handlebars. Version 4.3.0 can crash the Node.js process during output escaping when an async helper, registered with registerAsyncHelper, resolves to an object whose toHTML property is truthy but not callable. Handlebars escapeExpression calls the toHTML method on any value that has a truthy toHTML, so such a value throws a TypeError, and because the async substitution runs on a later tick outside the render function's try/catch, the throw is an uncaught exception that terminates the process without sending a response. Only version 4.3.0 is affected, since the throwing escape was introduced by the fix for CVE-2026-16231 and earlier versions do not escape async helper values. It can be triggered remotely when an async helper resolves to an externally influenced object such as parsed JSON. The issue is fixed in hbs 4.3.1, and users should upgrade to hbs 4.3.1 or later. | |
| Title | hbs vulnerable to Denial of Service via unhandled exception in async helper output escaping | |
| Weaknesses | CWE-248 | |
| References |
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| Metrics |
cvssV3_1
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