{"id":"UBUNTU-CVE-2026-42563","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's `ProcessMergeDriver` substitutes the file path (from the git tree, controllable by an attacker via a malicious branch) into the merge driver command via the `%P` placeholder and executes it with `subprocess.run(..., shell=True)`. An attacker who can cause a victim to merge an untrusted branch can achieve arbitrary command execution by crafting malicious file paths. Version 1.2.5 fixes the issue.","modified":"2026-06-17T06:31:21.128039524Z","published":"2026-06-10T23:16:00Z","upstream":["CVE-2026-42563"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-42563"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-42563"},{"type":"REPORT","url":"https://github.com/jelmer/dulwich/security/advisories/GHSA-9277-mp7x-85jf"}],"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-2026-42563.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_version":"0.18.5-1","binary_name":"pypy-dulwich"},{"binary_name":"python-dulwich","binary_version":"0.18.5-1"},{"binary_name":"python3-dulwich","binary_version":"0.18.5-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42563.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_version":"0.19.15-1build1","binary_name":"python3-dulwich"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42563.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-2026-42563.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_name":"python3-dulwich","binary_version":"0.21.6-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42563.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-2026-42563.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_version":"1.1.0-3","binary_name":"python3-dulwich"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42563.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}