{"id":"CVE-2026-47712","summary":"Dulwich doesn't sanitize commit subjects in `porcelain.format_patch`","details":"Dulwich is a pure-Python implementation of the Git file formats and protocols. Starting in version 0.24.0 and prior to version 1.2.5, dulwich.porcelain.format_patch(outdir=...) derives each patch filename from the commit's subject line. Prior to this fix, get_summary only replaced spaces with dashes - path separators (/, \\), parent-directory components (..), and other filename-hostile characters (e.g. :) were preserved verbatim and passed straight into os.path.join(outdir, f\"{i:04d}-{summary}.patch\"). A malicious commit subject could therefore direct the generated patch file outside the requested outdir. This is fixed in Dulwich 1.2.5. Users should upgrade to 1.2.5 or later. dulwich.patch.get_summary now mirrors git's format_sanitized_subject: only `[A-Za-z0-9._]` are kept, runs of other characters collapse to a single -, consecutive . collapse to a single ., trailing ./- are stripped, and the result is length-limited. This makes the returned string safe to embed as a filename component, so format_patch can no longer be steered out of outdir via the commit subject. Until upgrading, callers that pass untrusted commits to   porcelain.format_patch can use stdout=True and write the patch to a destination they control, rather than letting format_patch choose the filename; validate the chosen path before opening - e.g. compare os.path.realpath(returned_path) against  os.path.realpath(outdir) and reject any patch whose resolved path is not inside outdir; and/or pre-screen commits and refuse to format any whose subject's first line contains /, \\, .., or other characters that are not safe on the target filesystem.","aliases":["GHSA-555p-6grf-mh7f","PYSEC-2026-2462"],"modified":"2026-08-12T03:51:14.279391534Z","published":"2026-06-10T22:01:49.996Z","related":["openSUSE-SU-2026:10900-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-22"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47712.json"},"references":[{"type":"WEB","url":"https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47712.json"},{"type":"ADVISORY","url":"https://github.com/jelmer/dulwich/security/advisories/GHSA-555p-6grf-mh7f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47712"},{"type":"FIX","url":"https://github.com/jelmer/dulwich/commit/c2446e51b"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/jelmer/dulwich","events":[{"introduced":"031c690286ed5e6ddd199b4272587d590624b728"},{"fixed":"c2446e51b"},{"fixed":"073f4dfa9840af2da59887ed828b026b609faa6c"}],"database_specific":{"extracted_events":[{"introduced":"0.24.0"},{"fixed":"1.2.5"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["dulwich-1.2.4","dulwich-1.2.3","dulwich-1.2.2","dulwich-1.2.1","dulwich-1.2.0","dulwich-1.1.0","dulwich-1.0.0","dulwich-0.25.2","dulwich-0.25.1","dulwich-0.25.0","dulwich-0.24.8","dulwich-0.24.7","dulwich-0.24.6","dulwich-0.24.5","dulwich-0.24.2","dulwich-0.24.1","dulwich-0.24.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47712.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"}]}