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Vulnerabilities

Vulnerability · CVE-2026-33940

Handlebars provides the power necessary to let users build semantic templates.

Published Mar 27, 2026 · catalog updated Sep 4, 2026 · Handlebars provides the power

Check if you run it

No confirmed exploitation is on record for CVE-2026-33940. EPSS is 0.79%. Act only if a listed version of Handlebars provides the power is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Handlebars provides the power).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.79%
Remediation
Advisory link
Affected products
cpe handlebarsjs/handlebars

Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, a crafted object placed in the template context can bypass all conditional guards in and cause to return . The Handlebars runtime then treats the unresolved partial as a source that needs to be compiled, passing the crafted object to . Because the object is a valid Handlebars AST containing injected code, the generated JavaScript executes arbitrary commands on the server. The attack requires the adversary to control a value that can be returned by a dynamic partial lookup. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build ( ). Without , the fallback compilation path in is unreachable. Second, sanitize context data before rendering: Ensure no value in the context is a non-primitive object that could be passed to a dynamic partial. Third, avoid dynamic partial lookups ( ) when context data is user-controlled.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe handlebarsjs/handlebarsversion unspecified

How to fix CVE-2026-33940

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-33940. EPSS is 0.79%. Act only if a listed version of Handlebars provides the power is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-843: Access of Resource Using Incompatible Type (Type Confusion); CWE-94: Code Injection. EPSS 0.79%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 27, 2026 · NIST NVD

    Detected

    Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, a crafted object placed in the template context can bypass all conditional guards in and cause to return . The Handlebars runtime then treats the unresolved partial as a source that needs to be compiled, passing the crafted object to . Because the object is a valid Handlebars AST contain

  2. Sep 4, 2026 · NIST NVD

    Updated

    Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, a crafted object placed in the template context can bypass all conditional guards in and cause to return . The Handlebars runtime then treats the unresolved partial as a source that needs to be compiled, passing the crafted object to . Because the object is a valid Handlebars AST contain

Sources

  • CVE.orgVulnerability recordCVE-2026-33940

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33940

    30-day exploitation probability 0.8%

    first.org
  • NIST NVDVulnerability recordCVE-2026-33940

    Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, a crafted object placed in the template context can bypass all conditional guards in and cause to return . The Handlebar

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.