UBUNTU-CVE-2026-71554

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/CVE-2026-71554
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71554.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-71554
Upstream
Published
2026-08-07T00:00:00Z
Modified
2026-08-07T17:45:21.089999628Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.4.0 accept request header blocks containing more than one Host header, and forward every Host header to the consuming application. Where the consumer downgrades HTTP/2 to HTTP/1.1, the resulting request carries two Host header lines, providing a request smuggling primitive. This issue is fixed in version 4.4.1.

References

Affected packages

Ubuntu:18.04:LTS / python-h2

Package

Name
python-h2
Purl
pkg:deb/ubuntu/python-h2?arch=source&distro=bionic

Affected ranges

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

Affected versions

3.*
3.0.1-1
3.0.1-2
3.0.1-3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.0.1-3",
            "binary_name": "python-h2"
        },
        {
            "binary_version": "3.0.1-3",
            "binary_name": "python3-h2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71554.json"

Ubuntu:20.04:LTS / python-h2

Package

Name
python-h2
Purl
pkg:deb/ubuntu/python-h2?arch=source&distro=focal

Affected ranges

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

Affected versions

3.*
3.0.1-4
3.0.1-4.1ubuntu1
3.0.1-5
3.1.1-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.1.1-1",
            "binary_name": "python3-h2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71554.json"

Ubuntu:22.04:LTS / python-h2

Package

Name
python-h2
Purl
pkg:deb/ubuntu/python-h2?arch=source&distro=jammy

Affected ranges

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

Affected versions

4.*
4.0.0-3
4.1.0-3ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "4.1.0-3ubuntu1",
            "binary_name": "python3-h2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71554.json"

Ubuntu:24.04:LTS / python-h2

Package

Name
python-h2
Purl
pkg:deb/ubuntu/python-h2?arch=source&distro=noble

Affected ranges

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

Affected versions

4.*
4.1.0-4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "4.1.0-4",
            "binary_name": "python3-h2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71554.json"

Ubuntu:26.04:LTS / python-h2

Package

Name
python-h2
Purl
pkg:deb/ubuntu/python-h2?arch=source&distro=resolute

Affected ranges

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

Affected versions

4.*
4.2.0-1
4.3.0-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "4.3.0-1",
            "binary_name": "python3-h2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71554.json"