RCE in Express-Handlebars
CVE-2021-32820
Express-handlebars is a Handlebars view engine for Express. Express-handlebars mixes pure template data with engine configuration options through the Express render API. More specifically, the layout parameter may trigger file disclosure vulnerabilities in downstream applications. This potential vulnerability is somewhat restricted in that only files with existing extentions (i.e. file.extension) can be included, files that lack an extension will have .handlebars appended to them. For complete details refer to the referenced GHSL-2021-018 report. Notes in documentation have been added to help users avoid this potential information exposure vulnerability.
Vulnerability class: Information Disclosure
EPSS: 0.180 (96.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.
Affected products
- Express-handlebars — versions <= 5.3.2
- Express_handlebars_project Express_handlebars
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Third Party Advisory)
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Exploit, Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-32820?
- CVE-2021-32820 is a high-severity vulnerability in Express-Handlebars, classified under Information Disclosure. CVSS score: 8.6/10. Published 2021-05-14.
- How severe is CVE-2021-32820?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2021-32820 known to be exploited?
- 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.