{"cve":"CVE-2026-47712","nvd":{"published":"2026-06-10T23:16:48.650","modified":"2026-07-21T19:10:00.107","status":"Deferred","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","score":3.3},"cwes":["CWE-22"],"references":["https://github.com/jelmer/dulwich/commit/c2446e51b","https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5","https://github.com/jelmer/dulwich/security/advisories/GHSA-555p-6grf-mh7f"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-47712","score":0.00139,"percentile":0.03215,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-555p-6grf-mh7f","url":"https://osv.dev/vulnerability/GHSA-555p-6grf-mh7f","summary":"Dulwich doesn't sanitize commit subjects in `porcelain.format_patch`","modified":"2026-07-13T16:43:37.445090093Z","packages":[{"ecosystem":"PyPI","name":"dulwich","purl":"pkg:pypi/dulwich","ranges":[">=0.24.0 <1.2.5"],"fixed":["1.2.5"]}]},{"id":"PYSEC-2026-2462","url":"https://osv.dev/vulnerability/PYSEC-2026-2462","summary":"Dulwich doesn't sanitize commit subjects in `porcelain.format_patch`","modified":"2026-07-13T16:31:45.177098535Z","packages":[{"ecosystem":"PyPI","name":"dulwich","purl":"pkg:pypi/dulwich","ranges":[">=0.24.0 <1.2.5"],"fixed":["1.2.5"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}