UBUNTU-CVE-2026-47734

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Source
https://ubuntu.com/security/CVE-2026-47734
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47734.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-47734
Upstream
Published
2026-06-10T23:16:00Z
Modified
2026-06-17T06:31:24.732890435Z
Severity
  • 5.7 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Dulwich is a pure-Python implementation of the Git file formats and protocols. Starting in version 0.1.0 and prior to version 1.2.5, a client with push access could push a tiny crafted thin pack (~174 bytes) whose delta header declares a huge destsize. When dulwich ingested it via addthinpack / applydelta, it would allocate hundreds of MB of memory based on that attacker-controlled size, with no relationship to the actual bytes received. Operators running a Dulwich-based Git server that exposes git-receive-pack (i.e. accepts pushes) - for example via dulwich.server functionality, the HTTP smart server, or anything built on ReceivePackHandler - are impacted. The issue is patched in 1.2.5. addthinpack now accepts a maxinputsize keyword (bytes; 0/None = unlimited, matching git's semantics), and ReceivePackHandler reads receive.maxInputSize from the repository config and passes it through. Wire reads are counted and a PackInputTooLarge exception is raised once the cap is exceeded - equivalent to git index-pack --max-input-size. Users should upgrade to Dulwich 1.2.5 or later and set receive.maxInputSize in their server's repository config to a sane bound for their environment. On unpatched versions, receive.maxInputSize has no effect, so it cannot be used as a workaround. Until upgrading, operators should restrict dulwich-receive-pack (push) access to trusted, authenticated clients only, or disable it entirely on servers that only need to serve fetches and/or run the server under an OS-level memory limit (e.g. ulimit, cgroups/MemoryMax, or a container memory limit) so a malicious push is killed rather than taking down the host.

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_version": "0.12.0-1build2",
            "binary_name": "python-dulwich"
        },
        {
            "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-2026-47734.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_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-2026-47734.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-2026-47734.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-2026-47734.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-2026-47734.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-2026-47734.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-2026-47734.json"