{"id":"GHSA-pjvx-prjx-h659","summary":"nbconvert: Arbitrary file write through path traversal in cell output filenames when exporting to md, latex, rst and asciidoc","details":"### Summary\n\nnbconvert \u003c= v7.17.1 has an arbitrary file write vulnerability due to a path traversal in ipynb cell output metadata, more specifically on the filename attribute.\n\nVulnerable converters : `--to markdown`, `--to latex`, `--to rst`, `--to asciidoc`.\n\nIn `ExtractOutputPreprocessor`, `extractoutput.py:116-119` joins attacker-controlled  `path` to `output_files_dir` with no canonicalization check, enabling arbitrary file write.\n\nThis is a sibling vulnerability of https://github.com/advisories/GHSA-4c99-qj7h-p3vg.\n\n### Impact\n\nIf a victim runs nbconvert on a malicious ipynb file, it can create some files with arbitrary data in arbitrary locations, i.e. override authorized_keys.\n\nNote that running the cell with jupyter overrides the output, so it would \"clean up\" malicious cells.\n\n### PoC\n\nIn a ipynb file:\n\n```json\n\n\"cells\": [{\n        \"cell_type\": \"code\", \"id\": \"abc123\", \"execution_count\": 1,\n        \"metadata\": {}, \"source\": \"# PoC\",\n        \"outputs\": [{\n            \"output_type\": \"display_data\",\n            \"metadata\": {\n                \"filename\": \"../../../tmp/PWNED.png\"  # ← traverses outside output_dir\n            },\n            \"data\": {\n                # minimal valid PNG (1×1 pixel)\n                \"image/png\": \"iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==\"\n            }\n        }]\n    }]\n\n```\n\n\n### Patches\n\nFixed in \n- https://github.com/jupyter/nbconvert/commit/ce4bd99aec31d81d759fa8eeb8643179392ec66f\n- [7.17.2](https://github.com/jupyter/nbconvert/releases/tag/v7.17.2)","aliases":["CVE-2026-114140"],"modified":"2026-10-22T16:30:41.002101482Z","published":"2026-10-22T16:23:28Z","database_specific":{"github_reviewed_at":"2026-10-22T16:23:28Z","nvd_published_at":"2026-10-21T21:17:56Z","cwe_ids":["CWE-22"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/jupyter/nbconvert/security/advisories/GHSA-pjvx-prjx-h659"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114140"},{"type":"WEB","url":"https://github.com/jupyter/nbconvert/commit/ce4bd99aec31d81d759fa8eeb8643179392ec66f"},{"type":"PACKAGE","url":"https://github.com/jupyter/nbconvert"},{"type":"WEB","url":"https://github.com/jupyter/nbconvert/releases/tag/v7.17.2"}],"affected":[{"package":{"name":"nbconvert","ecosystem":"PyPI","purl":"pkg:pypi/nbconvert"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.4.0"},{"fixed":"7.17.2"}]}],"versions":["5.4.0","5.4.1","5.4.1.dev0","5.5.0","5.6.0","5.6.1","6.0.0","6.0.0a0","6.0.0a1","6.0.0a2","6.0.0a3","6.0.0a4","6.0.0a5","6.0.0a6","6.0.0b7","6.0.0rc0","6.0.1","6.0.2","6.0.3","6.0.4","6.0.5","6.0.6","6.0.7","6.1.0","6.1.0rc0","6.1.1b0","6.2.0","6.2.0rc0","6.2.0rc1","6.2.0rc2","6.3.0","6.3.0b0","6.4.0","6.4.1","6.4.2","6.4.3","6.4.4","6.4.5","6.5.0","6.5.1","6.5.2","6.5.3","6.5.4","7.0.0","7.0.0rc0","7.0.0rc1","7.0.0rc2","7.0.0rc3","7.1.0","7.10.0","7.11.0","7.12.0","7.13.0","7.13.1","7.14.0","7.14.1","7.14.2","7.15.0","7.16.0","7.16.1","7.16.2","7.16.3","7.16.4","7.16.5","7.16.6","7.17.0","7.17.1","7.2.0","7.2.1","7.2.10","7.2.2","7.2.3","7.2.4","7.2.5","7.2.6","7.2.7","7.2.8","7.2.9","7.3.0","7.3.1","7.4.0","7.5.0","7.6.0","7.7.0","7.7.1","7.7.2","7.7.3","7.7.4","7.8.0","7.9.0","7.9.1","7.9.2"],"database_specific":{"last_known_affected_version_range":"\u003c= 7.17.1","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-pjvx-prjx-h659/GHSA-pjvx-prjx-h659.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H"}]}