--- id: CVE-2019-9740 title: >- An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3 summary: >- An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. 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-93 vendor: python product: python affected: - 'python >= 2.0, < 2.7.17' - 'python >= 3.5.0, < 3.5.8' - 'python >= 3.6.0, < 3.6.9' - 'python >= 3.7.0, < 3.7.4' patched: - python 3.7.4 published: '2019-03-13' updated: '2026-10-07' sourceUpdated: '2026-10-07T19:17:15.167' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2019-9740' references: - url: 'http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00039.html' label: cve@mitre.org - url: 'http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00041.html' label: cve@mitre.org - url: >- http://packetstormsecurity.com/files/154927/Slackware-Security-Advisory-python-Updates.html label: cve@mitre.org - url: 'http://www.openwall.com/lists/oss-security/2021/02/04/2' label: cve@mitre.org - url: 'http://www.securityfocus.com/bid/107466' label: cve@mitre.org - url: 'https://access.redhat.com/errata/RHSA-2019:1260' label: cve@mitre.org - url: 'https://access.redhat.com/errata/RHSA-2019:2030' label: cve@mitre.org - url: 'https://access.redhat.com/errata/RHSA-2019:3335' label: cve@mitre.org - url: 'https://access.redhat.com/errata/RHSA-2019:3520' label: cve@mitre.org - url: 'https://access.redhat.com/errata/RHSA-2019:3725' label: cve@mitre.org - url: 'https://bugs.python.org/issue36276' label: cve@mitre.org - url: 'https://lists.debian.org/debian-lts-announce/2019/06/msg00022.html' label: cve@mitre.org - url: 'https://lists.debian.org/debian-lts-announce/2019/06/msg00023.html' label: cve@mitre.org - url: 'https://lists.debian.org/debian-lts-announce/2019/06/msg00026.html' label: cve@mitre.org - url: 'https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html' label: cve@mitre.org - url: 'https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html' label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ORNTF62QPLMJXIQ7KTZQ2776LMIXEKL/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/44TS66GJMO5H3RLMVZEBGEFTB6O2LJJU/ 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/JCPGLTTOBB3QEARDX4JOYURP6ELNNA2V/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JMWSKTNOHSUOT3L25QFJAVCFYZX46FYK/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JXASHCDD4PQFKTMKQN4YOP5ZH366ABN4/ label: cve@mitre.org - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M34WOYCDKTDE5KLUACE2YIEH7D37KHRX/ label: cve@mitre.org - url: 'https://seclists.org/bugtraq/2019/Oct/29' label: cve@mitre.org - url: 'https://security.gentoo.org/glsa/202003-26' label: cve@mitre.org - url: 'https://security.netapp.com/advisory/ntap-20190619-0005/' label: cve@mitre.org - url: 'https://usn.ubuntu.com/4127-1/' label: cve@mitre.org - url: 'https://usn.ubuntu.com/4127-2/' label: cve@mitre.org - url: 'https://www.oracle.com/security-alerts/cpujul2022.html' label: cve@mitre.org - url: 'http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00039.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00041.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: >- http://packetstormsecurity.com/files/154927/Slackware-Security-Advisory-python-Updates.html label: af854a3a-2127-422b-91ae-364da2661108 - url: 'http://www.openwall.com/lists/oss-security/2021/02/04/2' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'http://www.securityfocus.com/bid/107466' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://access.redhat.com/errata/RHSA-2019:1260' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://access.redhat.com/errata/RHSA-2019:2030' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://access.redhat.com/errata/RHSA-2019:3335' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://access.redhat.com/errata/RHSA-2019:3520' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://access.redhat.com/errata/RHSA-2019:3725' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://bugs.python.org/issue36276' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2019/06/msg00022.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2019/06/msg00023.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://lists.debian.org/debian-lts-announce/2019/06/msg00026.html' 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.debian.org/debian-lts-announce/2020/08/msg00034.html' label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ORNTF62QPLMJXIQ7KTZQ2776LMIXEKL/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/44TS66GJMO5H3RLMVZEBGEFTB6O2LJJU/ 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/JCPGLTTOBB3QEARDX4JOYURP6ELNNA2V/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JMWSKTNOHSUOT3L25QFJAVCFYZX46FYK/ label: af854a3a-2127-422b-91ae-364da2661108 - url: >- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JXASHCDD4PQFKTMKQN4YOP5ZH366ABN4/ 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://seclists.org/bugtraq/2019/Oct/29' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://security.gentoo.org/glsa/202003-26' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://security.netapp.com/advisory/ntap-20190619-0005/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://usn.ubuntu.com/4127-1/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://usn.ubuntu.com/4127-2/' label: af854a3a-2127-422b-91ae-364da2661108 - url: 'https://www.oracle.com/security-alerts/cpujul2022.html' label: af854a3a-2127-422b-91ae-364da2661108 tags: - nvd - cve.org epss: 0.05372 epssPercentile: 0.92431 ssvc: exploitation: none automatable: 'no' technicalImpact: partial timestamp: '2026-10-07T18:21:59.590346Z' scores: nvd: 6.1 adp: 6.5 ingestedAt: '2026-10-07T18:42:20.897Z' --- ## Overview An issue was discovered in urllib2 in Python 2.x through 2.7.16 and urllib in Python 3.x through 3.7.3. 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 query string after a ? character) followed by an HTTP header or a Redis command. This is fixed in: v2.7.17, v2.7.17rc1, v2.7.18, v2.7.18rc1; v3.5.10, v3.5.10rc1, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.9, v3.6.9rc1; v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9. ## Affected - `python >= 2.0, < 2.7.17` - `python >= 3.5.0, < 3.5.8` - `python >= 3.6.0, < 3.6.9` - `python >= 3.7.0, < 3.7.4` ## Remediation Upgrade past the affected range: - `python 3.7.4`