Versions of handlebars prior to 3.0.8 or 4.5.3 are vulnerable to prototype pollution. It is possible to add or modify properties to the Object prototype through a malicious template. This may allow attackers to crash the application or execute Arbitrary Code in specific conditions.

Recommendation

Upgrade to version 3.0.8, 4.5.3 or later.

References

• https://www.npmjs.com/advisories/1325