{"id":"USN-5201-1","summary":"python3.8, python3.9 vulnerabilities","details":"\nIt was discovered that the Python urllib http client could enter into an infinite \nloop when incorrectly handling certain server responses (100 Continue response). \nSpecially crafted traffic from a malicious HTTP server could cause a denial of \nservice (Dos) condition for a client.\n\n","modified":"2026-04-22T10:19:51.665598Z","published":"2021-12-17T15:10:44Z","related":["UBUNTU-CVE-2021-3737"],"upstream":["CVE-2021-3737","UBUNTU-CVE-2021-3737"],"references":[{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-5201-1"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-3737"}],"affected":[{"package":{"name":"python3.8","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python3.8@3.8.10-0ubuntu1~20.04.2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.8.10-0ubuntu1~20.04.2"}]}],"versions":["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_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-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-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","binary_version":"3.8.10-0ubuntu1~20.04.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-5201-1.json","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"}]}}},{"package":{"name":"python3.9","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python3.9@3.9.5-3ubuntu0~20.04.1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.9.5-3ubuntu0~20.04.1"}]}],"versions":["3.9.0~rc1-1~20.04","3.9.0-5~20.04","3.9.5-3~20.04.1"],"ecosystem_specific":{"binaries":[{"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-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-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","binary_version":"3.9.5-3ubuntu0~20.04.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-5201-1.json","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"}]}}}],"schema_version":"1.7.5"}