USN-5201-1

See a problem?
Please try reporting it to the source first.
Source
https://ubuntu.com/security/notices/USN-5201-1
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-5201-1.json
JSON Data
https://api.osv.dev/v1/vulns/USN-5201-1
Upstream
Related
Published
2021-12-17T15:10:44.332712Z
Modified
2025-12-19T22:21:17.192275Z
Summary
python3.8, python3.9 vulnerabilities
Details

It was discovered that the Python urllib http client could enter into an infinite loop when incorrectly handling certain server responses (100 Continue response). Specially crafted traffic from a malicious HTTP server could cause a denial of service (Dos) condition for a client.

References

Affected packages

Ubuntu:20.04:LTS / python3.8

Package

Name
python3.8
Purl
pkg:deb/ubuntu/python3.8@3.8.10-0ubuntu1~20.04.2?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
3.8.10-0ubuntu1~20.04.2

Affected versions

3.*

3.8.0-1
3.8.0-2
3.8.0-3
3.8.0-4
3.8.0-5
3.8.1-2ubuntu3
3.8.2~rc1-1ubuntu1
3.8.2-1
3.8.2-1ubuntu1
3.8.2-1ubuntu1.1
3.8.2-1ubuntu1.2
3.8.5-1~20.04
3.8.5-1~20.04.2
3.8.5-1~20.04.3
3.8.10-0ubuntu1~20.04
3.8.10-0ubuntu1~20.04.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "idle-python3.8"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "libpython3.8"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "libpython3.8-dev"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "libpython3.8-minimal"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "libpython3.8-stdlib"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "libpython3.8-testsuite"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "python3.8"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "python3.8-dev"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "python3.8-examples"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "python3.8-full"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "python3.8-minimal"
        },
        {
            "binary_version": "3.8.10-0ubuntu1~20.04.2",
            "binary_name": "python3.8-venv"
        }
    ],
    "availability": "No subscription required"
}

Database specific

cves_map

{
    "ecosystem": "Ubuntu:20.04:LTS",
    "cves": [
        {
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ],
            "id": "CVE-2021-3737"
        }
    ]
}

Ubuntu:20.04:LTS / python3.9

Package

Name
python3.9
Purl
pkg:deb/ubuntu/python3.9@3.9.5-3ubuntu0~20.04.1?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
3.9.5-3ubuntu0~20.04.1

Affected versions

3.*

3.9.0~rc1-1~20.04
3.9.0-5~20.04
3.9.5-3~20.04.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "idle-python3.9"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "libpython3.9"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "libpython3.9-dev"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "libpython3.9-minimal"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "libpython3.9-stdlib"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "libpython3.9-testsuite"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "python3.9"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "python3.9-dev"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "python3.9-examples"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "python3.9-full"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "python3.9-minimal"
        },
        {
            "binary_version": "3.9.5-3ubuntu0~20.04.1",
            "binary_name": "python3.9-venv"
        }
    ],
    "availability": "No subscription required"
}

Database specific

cves_map

{
    "ecosystem": "Ubuntu:20.04:LTS",
    "cves": [
        {
            "severity": [
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                    "type": "CVSS_V3"
                },
                {
                    "score": "medium",
                    "type": "Ubuntu"
                }
            ],
            "id": "CVE-2021-3737"
        }
    ]
}