UBUNTU-CVE-2026-42305

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-42305
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42305.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-42305
Upstream
  • CVE-2026-42305
Published
2026-06-10T23:16:00Z
Modified
2026-06-17T06:31:20.896554055Z
Severity
  • 8.8 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Dulwich is a pure-Python implementation of the Git file formats and protocols. Versions starting with 0.10.0 and prior to 1.2.5 have an arbitrary file write leading to remote code execution when cloning or checking out a malicious Git repository on Windows. Dulwich's path-element validator accepted tree entries whose filenames contained bytes that Windows interprets as structural path syntax. Contributing configuration bugs made matters worse. The core.protectNTFS and core.protectHFS settings were looked up under a wrong option name and so user-set values were silently ignored, and core.protectNTFS only defaulted to true on Windows (Git upstream has defaulted it to true everywhere since CVE-2019-1353). Both have been corrected. Anyone who clones, fetches, or checks out an untrusted repository with Dulwich on Windows - either through the Dulwich CLI, porcelain.clone, or any downstream tool built on Dulwich - is impacted. POSIX clones are not directly exploitable (on POSIX \ is a literal filename byte), but a POSIX user can unknowingly propagate a malicious tree to Windows consumers via push or re-publication. This issue is fixed in Dulwich 1.2.5. Users should upgrade to 1.2.5 or later. There is no effective pre-patch workaround. On affected versions the core.protectNTFS configuration key was silently ignored, so setting it to true does not mitigate the issue. Users who cannot upgrade should avoid cloning, fetching, or checking out untrusted repositories with Dulwich on Windows. After upgrading the NTFS validator is on by default on every platform, so no additional configuration is required.

References

Affected packages

Ubuntu:16.04:LTS
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
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-2026-42305.json"
Ubuntu:18.04:LTS
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.18.2-1build1
0.18.5-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "pypy-dulwich",
            "binary_version": "0.18.5-1"
        },
        {
            "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-2026-42305.json"
Ubuntu:20.04:LTS
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
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-2026-42305.json"
Ubuntu:22.04:LTS
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.20.15-1ubuntu1
0.20.31-1ubuntu1
0.20.31-1.1
0.20.31-1.1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-dulwich",
            "binary_version": "0.20.31-1.1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42305.json"
Ubuntu:24.04:LTS
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
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-2026-42305.json"
Ubuntu:25.10
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
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-2026-42305.json"
Ubuntu:26.04:LTS
dulwich

Package

Name
dulwich
Purl
pkg:deb/ubuntu/dulwich?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.22.7-1
0.24.2-2
1.*
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-2026-42305.json"