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Vulnerability record · CVE-2019-9740 · published 13 March 2019

CVE-2019-9740: Python vulnerability

Python · Python

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.

6.1 CVSS 3.1 Medium EPSS 5.4% · top 7.6% CWE-93 · CWE-93
6.1CVSS 3.1 base score, v2 4.3
5.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
58References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00039.html Mailing ListThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00041.html Mailing ListThird Party Advisory
http://packetstormsecurity.com/files/154927/Slackware-Security-Advisory-python-Updates.html Third Party AdvisoryVDB Entry
http://www.openwall.com/lists/oss-security/2021/02/04/2 Mailing ListThird Party Advisory
http://www.securityfocus.com/bid/107466 Third Party AdvisoryVDB Entry
https://access.redhat.com/errata/RHSA-2019:1260 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2030 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3335 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3520 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3725 Third Party Advisory
https://bugs.python.org/issue36276 ExploitIssue TrackingVendor Advisory
https://lists.debian.org/debian-lts-announce/2019/06/msg00022.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2019/06/msg00023.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2019/06/msg00026.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/07/msg00011.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/08/msg00034.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ORNTF62QPLMJXIQ7KTZQ27
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/44TS66GJMO5H3RLMVZEBGEF
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4X3HW5JRZ7GCPSR7UHJOLD7
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JCPGLTTOBB3QEARDX4JOYUR
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JMWSKTNOHSUOT3L25QFJAVC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JXASHCDD4PQFKTMKQN4YOP5
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M34WOYCDKTDE5KLUACE2YIE
https://seclists.org/bugtraq/2019/Oct/29 Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202003-26 Third Party Advisory
https://security.netapp.com/advisory/ntap-20190619-0005/ Third Party Advisory
https://usn.ubuntu.com/4127-1/ Third Party Advisory
https://usn.ubuntu.com/4127-2/ Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00039.html Mailing ListThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00041.html Mailing ListThird Party Advisory
http://packetstormsecurity.com/files/154927/Slackware-Security-Advisory-python-Updates.html Third Party AdvisoryVDB Entry
http://www.openwall.com/lists/oss-security/2021/02/04/2 Mailing ListThird Party Advisory
http://www.securityfocus.com/bid/107466 Third Party AdvisoryVDB Entry
https://access.redhat.com/errata/RHSA-2019:1260 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:2030 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3335 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3520 Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:3725 Third Party Advisory
https://bugs.python.org/issue36276 ExploitIssue TrackingVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2019-9740), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.