{"id":"CVE-2026-33686","aliases":["GHSA-9ffq-6457-8958"],"url":"https://o3.security/vulnerability/CVE-2026-33686","summary":"Sharp is Vulnerable to Path Traversal via Unsanitized Extension in FileUtil","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'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.\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).","published":"2026-03-26T21:54:25.294Z","modified":"2026-08-12T03:51:31.304393760Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"code16/sharp","fixedVersion":"9.20.0"}],"fix":{"url":"https://github.com/code16/sharp/pull/715","label":"code16/sharp#715"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33686.json"},{"type":"ADVISORY","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":"FIX","url":"https://github.com/code16/sharp/pull/715"},{"type":"PACKAGE","url":"https://github.com/code16/sharp"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:31.304393760Z"}}