Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
CVE-2026-33941
handlebars-lang handlebars.js — Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L R C H H H 8.2 .0022 11.3 —
AFFECTED
Product Versions Fixed
handlebars.js >= 4.0.0, < 4.7.9 – —
TIMELINE
Mar 24 Reserved by GitHub_M
Mar 27 Published (CNA: GitHub_M)
Sep 1 EXPLOIT PUBLISHED — CVE-2026-33941 (handlebars-lang handlebars.js). Public exploit reference added.
Sep 1 RESCORED — CVE-2026-33941 (handlebars-lang handlebars.js). CVSS 8.3 → 8.2 (NVD).
Sep 4 EXPLOIT PUBLISHED — CVE-2026-33941 (handlebars-lang handlebars.js). Public exploit reference added.
Description
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the Handlebars CLI precompiler (`bin/handlebars` / `lib/precompiler.js`) concatenates user-controlled strings — template file names and several CLI options — directly into the JavaScript it emits, without any escaping or sanitization. An attacker who can influence template filenames or CLI arguments can inject arbitrary JavaScript that executes when the generated bundle is loaded in Node.js or a browser. Version 4.7.9 fixes the issue. Some workarounds are available. First, validate all CLI inputs before invoking the precompiler. Reject filenames and option values that contain characters with JavaScript string-escaping significance (`"`, `'`, `;`, etc.). Second, use a fixed, trusted namespace string passed via a configuration file rather than command-line arguments in automated pipelines. Third, run the precompiler in a sandboxed environment (container with no write access to sensitive paths) to limit the impact of successful exploitation. Fourth, audit template filenames in any repository or package that is consumed by an automated build pipeline.
Lifecycle
Complete event history — 5 events, chronological
| Date | Event | Detail |
|---|
| March 24, 2026 | Reserved | Reserved by GitHub_M |
| March 27, 2026 | Published | Published (CNA: GitHub_M) |
| September 1, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-33941 (handlebars-lang handlebars.js). Public exploit reference added. |
| September 1, 2026 | RESCORED | RESCORED — CVE-2026-33941 (handlebars-lang handlebars.js). CVSS 8.3 → 8.2 (NVD). |
| September 4, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-33941 (handlebars-lang handlebars.js). Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| handlebars-lang | handlebars.js | — | >= 4.0.0, < 4.7.9 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-33941 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.
