CVE-2019-11236: Urllib3 Improper Neutralization Of CRLF Sequences Vulnerability
MODERATECVE-2019-11236 is a MODERATE (CVSS 6.1) improper neutralization of crlf sequences vulnerability (CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')) affecting Urllib3 libraries in the PyPI ecosystem. The issue involves improper neutralization of crlf sequences in urllib3 library for python. Remediation is available by upgrading affected packages to version 1.24.3.
CVE-2019-11236 at a Glance
Security Impact
CVSS: 6.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).
How to Fix CVE-2019-11236
To remediate this vulnerability, upgrade all affected Urllib3 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
pip install urllib3>=1.24.3Run the following command in your project directory to verify that all resolved dependencies use the patched release:
pip show urllib3How to Check if You Are Affected
To determine whether your Python environment is affected by CVE-2019-11236, inspect your installed packages using pip:
pip show urllib3Analyze the terminal output to locate any version of Urllib3 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.24.3), your application is affected.
Note: The pip show urllib3 command checks currently installed packages in your active Python environment.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection'), where the product uses crlf (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes crlf sequences from inputs. In Urllib3, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2019-11236 Affected Urllib3 Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
urllib3
|
PyPI |
< 1.24.3
|
1.24.3
|
References
Frequently Asked Questions
What is CVE-2019-11236?
Which Urllib3 versions are affected?
What version fixes CVE-2019-11236?
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What CWE is associated with CVE-2019-11236?
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Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-r64q-w8jr-g9qp",
"modified" : "2024-11-18T22:52:14Z",
"published" : "2022-05-13T01:09:23Z",
"aliases" : [ "CVE-2019-11236" ],
"summary" : "Improper Neutralization of CRLF Sequences in urllib3 library for Python",
"details" : "In the urllib3 library through 1.24.2 for Python, CRLF injection is possible if the attacker controls the request parameter.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
}, {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "PyPI",
"name" : "urllib3"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.24.3"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 1.24.2"
}
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-11236"
}, {
"type" : "WEB",
"url" : "https://github.com/urllib3/urllib3/issues/1553"
}, {
"type" : "WEB",
"url" : "https://usn.ubuntu.com/3990-2"
}, {
"type" : "WEB",
"url" : "https://usn.ubuntu.com/3990-1"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XOSA2NT4DUQDBEIWE6O7KKD24XND7TE2"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TBI45HO533KYHNB5YRO43TBYKA3E3VRL"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R62XGEYPUTXMRHGX5I37EBCGQ5COHGKR"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NKGPJLVLVYCL4L4B4G5TIOTVK4BKPG72"
}, {
"type" : "WEB",
"url" : "https://lists.debian.org/debian-lts-announce/2023/10/msg00012.html"
}, {
"type" : "WEB",
"url" : "https://lists.debian.org/debian-lts-announce/2021/06/msg00015.html"
}, {
"type" : "WEB",
"url" : "https://lists.debian.org/debian-lts-announce/2019/06/msg00016.html"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/urllib3/urllib3"
}, {
"type" : "WEB",
"url" : "https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2019-132.yaml"
}, {
"type" : "ADVISORY",
"url" : "https://github.com/advisories/GHSA-r64q-w8jr-g9qp"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2019:3590"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2019:3335"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2019:2272"
}, {
"type" : "WEB",
"url" : "http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00039.html"
}, {
"type" : "WEB",
"url" : "http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00041.html"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-93" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2022-06-28T15:02:18Z",
"nvd_published_at" : "2019-04-15T15:29:00Z"
}
}