--- id: CVE-2019-18348 title: >- An issue was discovered in urllib2 in Python 2.x through 2.7.17 and urllib in Python 3.x through 3.8.0 summary: >- An issue was discovered in urllib2 in Python 2.x through 2.7.17 and urllib in Python 3.x through 3.8.0. CRLF injection is possible if the attacker controls a url parameter, as demonstrated by the first argument to urllib.request.urlopen … severity: medium cvss: 6.1 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N' cwe: - CWE-74 vendor: python product: python affected: - 'python >= 2.0, <= 2.7.17' - 'python >= 3.0, < 3.5.10' - 'python >= 3.6.0, < 3.6.11' - 'python >= 3.7.0, < 3.7.8' - 'python >= 3.8.0, < 3.8.3' patched: - python 3.8.3 published: '2019-10-23' updated: '2026-10-07' sourceUpdated: '2026-10-07T19:17:13.663' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2019-18348' references: - url: 'http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00041.html' label: cve@mitre.org - url: 'https://bugs.python.org/issue30458#msg347282' label: cve@mitre.org - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1727276' label: cve@mitre.org - url: 'https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html' label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4X3HW5JRZ7GCPSR7UHJOLD7AWLTQCDVR/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A5NSAX4SC3V64PGZUPH7PRDLSON34Q5A/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JCPGLTTOBB3QEARDX4JOYURP6ELNNA2V/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M34WOYCDKTDE5KLUACE2YIEH7D37KHRX/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UESGYI5XDAHJBATEZN3MHNDUBDH47AS6/ label: cve@mitre.org - url: 'https://security.netapp.com/advisory/ntap-20191107-0004/' label: cve@mitre.org - url: 'https://usn.ubuntu.com/4333-1/' label: cve@mitre.org - url: 'https://usn.ubuntu.com/4333-2/' label: cve@mitre.org - url: 'https://www.oracle.com/security-alerts/cpuoct2020.html' label: cve@mitre.org - url: 'http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00041.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://bugs.python.org/issue30458#msg347282' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1727276' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4X3HW5JRZ7GCPSR7UHJOLD7AWLTQCDVR/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A5NSAX4SC3V64PGZUPH7PRDLSON34Q5A/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JCPGLTTOBB3QEARDX4JOYURP6ELNNA2V/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M34WOYCDKTDE5KLUACE2YIEH7D37KHRX/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UESGYI5XDAHJBATEZN3MHNDUBDH47AS6/ label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://security.netapp.com/advisory/ntap-20191107-0004/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://usn.ubuntu.com/4333-1/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://usn.ubuntu.com/4333-2/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://www.oracle.com/security-alerts/cpuoct2020.html' label: af854a3a-2127-422b-91ae-364da2661108 tags: - nvd - cve.org epss: 0.03513 epssPercentile: 0.88861 ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2026-10-07T18:00:08.130814Z' scores: nvd: 6.1 adp: 5.4 ingestedAt: '2026-10-07T18:42:20.910Z' --- ## Overview An issue was discovered in urllib2 in Python 2.x through 2.7.17 and urllib in Python 3.x through 3.8.0. CRLF injection is possible if the attacker controls a url parameter, as demonstrated by the first argument to urllib.request.urlopen with \r\n (specifically in the host component of a URL) followed by an HTTP header. This is similar to the CVE-2019-9740 query string issue and the CVE-2019-9947 path string issue. (This is not exploitable when glibc has CVE-2016-10739 fixed.). This is fixed in: v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1; v3.6.11, v3.6.11rc1, v3.6.12; v3.7.8, v3.7.8rc1, v3.7.9; v3.8.3, v3.8.3rc1, v3.8.4, v3.8.4rc1, v3.8.5, v3.8.6, v3.8.6rc1. ## Affected - `python >= 2.0, <= 2.7.17` - `python >= 3.0, < 3.5.10` - `python >= 3.6.0, < 3.6.11` - `python >= 3.7.0, < 3.7.8` - `python >= 3.8.0, < 3.8.3` ## Remediation Upgrade past the affected range: - `python 3.8.3`