CVE-2019-20920
Description
Handlebars before 3.0.8 and 4.x before 4.5.3 is vulnerable to Arbitrary Code Execution. The lookup helper fails to properly validate templates, allowing attackers to submit templates that execute arbitrary JavaScript. This can be used to run arbitrary code on a server processing Handlebars templates or in a victim's browser (effectively serving as XSS).
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | fixed | 3:4.5.3-1 |
| debian | bullseye | fixed | 3:4.5.3-1 |
| debian | forky | fixed | 3:4.5.3-1 |
| debian | sid | fixed | 3:4.5.3-1 |
| debian | trixie | fixed | 3:4.5.3-1 |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| npm | handlebars | <3.0.8 | 3.0.8 |
| npm | handlebars | >=4.0.0,<4.5.3 | 4.5.3 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2019-20920
- https://github.com/handlebars-lang/handlebars.js/commit/156061eb7707575293613d7fdf90e2bdaac029ee
- https://github.com/handlebars-lang/handlebars.js/commit/d54137810a49939fd2ad01a91a34e182ece4528e
- https://snyk.io/vuln/SNYK-JS-HANDLEBARS-534478
- https://www.npmjs.com/advisories/1316
- https://www.npmjs.com/advisories/1324
- https://www.npmjs.com/package/handlebars
- https://security-tracker.debian.org/tracker/CVE-2019-20920
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.