{"id":"UBUNTU-CVE-2026-47712","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.","modified":"2026-06-17T06:31:29.613602784Z","published":"2026-06-10T23:16:00Z","upstream":["CVE-2026-47712"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-47712"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-47712"},{"type":"REPORT","url":"https://github.com/jelmer/dulwich/security/advisories/GHSA-555p-6grf-mh7f"}],"affected":[{"package":{"name":"dulwich","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.11.2-1ubuntu1","0.12.0-1","0.12.0-1build1","0.12.0-1build2"],"ecosystem_specific":{"binaries":[{"binary_name":"pypy-dulwich","binary_version":"0.12.0-1build2"},{"binary_name":"python-dulwich","binary_version":"0.12.0-1build2"},{"binary_name":"python3-dulwich","binary_version":"0.12.0-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}},{"package":{"name":"dulwich","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.18.2-1build1","0.18.5-1"],"ecosystem_specific":{"binaries":[{"binary_name":"pypy-dulwich","binary_version":"0.18.5-1"},{"binary_version":"0.18.5-1","binary_name":"python-dulwich"},{"binary_version":"0.18.5-1","binary_name":"python3-dulwich"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}},{"package":{"name":"dulwich","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.11-2","0.19.14-4ubuntu1","0.19.15-1","0.19.15-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"pypy-dulwich","binary_version":"0.19.15-1build1"},{"binary_name":"python3-dulwich","binary_version":"0.19.15-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}},{"package":{"name":"dulwich","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.20.15-1ubuntu1","0.20.31-1ubuntu1","0.20.31-1.1","0.20.31-1.1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.20.31-1.1build1","binary_name":"python3-dulwich"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}},{"package":{"name":"dulwich","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.21.6-1","0.21.6-1build1","0.21.6-1build2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.21.6-1build2","binary_name":"python3-dulwich"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}},{"package":{"name":"dulwich","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.22.7-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-dulwich","binary_version":"0.22.7-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}},{"package":{"name":"dulwich","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/dulwich?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.22.7-1","0.24.2-2","1.1.0-2ubuntu1","1.1.0-3"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-dulwich","binary_version":"1.1.0-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47712.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}