GHSA-9FFQ-6457-8958

Vulnerability from github – Published: 2026-03-25 20:01 – Updated: 2026-03-27 21:36
VLAI?
Summary
Sharp is Vulnerable to Path Traversal via Unsanitized Extension in FileUtil
Details

Summary

A path traversal vulnerability exists in the FileUtil class of the code16/sharp package. The application fails to sanitize file extensions properly, allowing path separators to be passed into the storage layer.

Detail

In src/Utils/FileUtil.php, the FileUtil::explodeExtension() function extracts a file's extension by splitting the filename at the last dot. However, the extracted extension is never sanitized. While the application uses a normalizeName() function, this function only cleans the base filename, meaning any path separators (such as /) injected into the extension will survive and be passed into the storeAs() function.

Impact

Exploiting this flaw allows an authenticated attacker to manipulate file paths: - Files can be written outside of the intended tmp directory via path traversal. For more details on the package, visit: https://github.com/code16/sharp - Existing critical files (such as .env or configuration files) could potentially be overwritten. Review the CWE definition here: https://cwe.mitre.org/data/definitions/22.html (Note: This vulnerability was successfully chained with CWE-434 in a local Proof of Concept to confirm the traversal.)

Patches

This issue has been patched by properly sanitizing the extension using pathinfo(PATHINFO_EXTENSION) instead of strrpos(), alongside applying strict regex replacements to both the base name and the extension. The fix is available in pull request #715

Credits

Reported by zaurgsynv.

Severity ?
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "code16/sharp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "9.20.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33686"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-25T20:01:04Z",
    "nvd_published_at": "2026-03-26T22:16:31Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nA path traversal vulnerability exists in the FileUtil class of the code16/sharp package. The application fails to sanitize file extensions properly, allowing path separators to be passed into the storage layer.\n\n### Detail\nIn `src/Utils/FileUtil.php`, the `FileUtil::explodeExtension()` function extracts a file\u0027s extension by splitting the filename at the last dot. However, the extracted extension is never sanitized. While the application uses a `normalizeName()` function, this function only cleans the base filename, meaning any path separators (such as /) injected into the extension will survive and be passed into the `storeAs()` function.\n\n### Impact\nExploiting this flaw allows an authenticated attacker to manipulate file paths:\n- Files can be written outside of the intended tmp directory via path traversal. For more details on the package, visit: https://github.com/code16/sharp\n- Existing critical files (such as .env or configuration files) could potentially be overwritten. Review the CWE definition here: https://cwe.mitre.org/data/definitions/22.html (Note: This vulnerability was successfully chained with CWE-434 in a local Proof of Concept to confirm the traversal.)\n\n### Patches\nThis issue has been patched by properly sanitizing the extension using `pathinfo(PATHINFO_EXTENSION)` instead of `strrpos()`, alongside applying strict regex replacements to both the base name and the extension. The fix is available in pull request #715\n\n### Credits\nReported by [zaurgsynv](https://github.com/zaurgsynv).",
  "id": "GHSA-9ffq-6457-8958",
  "modified": "2026-03-27T21:36:04Z",
  "published": "2026-03-25T20:01:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/code16/sharp/security/advisories/GHSA-9ffq-6457-8958"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33686"
    },
    {
      "type": "WEB",
      "url": "https://github.com/code16/sharp/pull/715"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/code16/sharp"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Sharp is Vulnerable to Path Traversal via Unsanitized Extension in FileUtil"
}


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  • 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.
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  • 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.



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