CVE-2014-3146: Lxml Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-57qw-cc2g-pv5p
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2014-3146 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Lxml libraries in the PyPI ecosystem. The issue involves lxml cross-site scripting via control characters. Remediation is available by upgrading affected packages to version 3.3.5.

CVE-2014-3146 at a Glance

CVE Identifier CVE-2014-3146
GHSA Identifier GHSA-57qw-cc2g-pv5p
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Lxml
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2014-3146

To remediate this vulnerability, upgrade all affected Lxml dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

lxml fixed: 3.3.5 
pip install lxml>=3.3.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show lxml

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2014-3146, inspect your installed packages using pip:

pip show lxml

Analyze the terminal output to locate any version of Lxml in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.3.5), your application is affected.

Note: The pip show lxml command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Lxml, 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

Incomplete blacklist vulnerability in the `lxml.html.clean` module in lxml before 3.3.5 allows remote attackers to conduct cross-site scripting (XSS) attacks via control characters in the link scheme to the `clean_html` function.

CVE-2014-3146 Affected Lxml Versions

1 component(s)
Fixed Versions:
3.3.5
Product / Package Ecosystem Affected Versions Fixed Version
lxml
pypi/lxml
PyPI
< 3.3.5
3.3.5

References

NVD — CVE-2014-3146 NVD
https://nvd.nist.gov/vuln/detail/CVE-2014-3146
Lxml Source Repository REPOSITORY
https://github.com/lxml/lxml/pull/273
Security Fix Commit FIX COMMIT
https://github.com/lxml/lxml/commit/3f3082e0a67851cde26a48da3d1f4b75d8aa07ec
Security Fix Commit FIX COMMIT
https://github.com/lxml/lxml/commit/86e81ab393ba14c1be71284675851a3bdce57d69
Security Fix Commit FIX COMMIT
https://github.com/lxml/lxml/commit/e86b294f1f81b899a59925123560ff924a72f1cc
Lxml Source Repository REPOSITORY
https://github.com/lxml/lxml
Lxml Security Information SECURITY
http://lxml.de/3.3/changes-3.3.5.html
Lxml Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2014-9.yaml
mailman-mail5.webfaction.com/pipermail/lxml/2014... WEB
https://mailman-mail5.webfaction.com/pipermail/lxml/2014-April/007128.html
web.archive.org/web/20140724172044/... WEB
https://web.archive.org/web/20140724172044/http://secunia.com/advisories/58013
web.archive.org/web/20140805110535/... WEB
https://web.archive.org/web/20140805110535/http://secunia.com/advisories/59008
web.archive.org/web/20140806061046/... WEB
https://web.archive.org/web/20140806061046/http://secunia.com/advisories/58744
web.archive.org/web/20141017122607/... WEB
https://web.archive.org/web/20141017122607/https://mailman-mail5.webfaction.com/pipermail/lxml/2014-April/007128.html
Lxml Security Information SECURITY
https://web.archive.org/web/20150523055039/http://www.mandriva.com/en/support/security/advisories/advisory/MDVSA-2015:112/?name=MDVSA-2015:112
Lxml Security Information SECURITY
https://web.archive.org/web/20200228180542/http://www.securityfocus.com/bid/67159
advisories.mageia.org/mgasa-2014-0218.htm... WEB
http://advisories.mageia.org/MGASA-2014-0218.html
lists.opensuse.org/opensuse-updates/20... WEB
http://lists.opensuse.org/opensuse-updates/2014-05/msg00083.html
seclists.org/fulldisclosure/2014... WEB
http://seclists.org/fulldisclosure/2014/Apr/210
seclists.org/fulldisclosure/2014... WEB
http://seclists.org/fulldisclosure/2014/Apr/319
Lxml Security Information SECURITY
http://www.debian.org/security/2014/dsa-2941
Lxml Security Information SECURITY
http://www.openwall.com/lists/oss-security/2014/05/09/7
www.ubuntu.com/usn/usn-2217-1 WEB
http://www.ubuntu.com/usn/USN-2217-1

Frequently Asked Questions

What is CVE-2014-3146?
CVE-2014-3146 is a security vulnerability in Lxml involving lxml Cross-site Scripting Via Control Characters under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Lxml versions are affected?
Affected versions include releases prior to 3.3.5 across affected packages: lxml.
What version fixes CVE-2014-3146?
Upgrading to 3.3.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is lxml affected?
Yes, lxml is affected in releases prior to 3.3.5. Upgrade your dependency to 3.3.5 or later.
What is the CVSS score of CVE-2014-3146?
CVE-2014-3146 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2014-3146?
CVE-2014-3146 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check PyPI dependencies for CVE-2014-3146?
Run the dependency tree command: 'pip show lxml'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-57qw-cc2g-pv5p",
  "modified" : "2024-09-30T17:03:32Z",
  "published" : "2022-05-14T04:01:59Z",
  "aliases" : [ "CVE-2014-3146" ],
  "summary" : "lxml Cross-site Scripting Via Control Characters",
  "details" : "Incomplete blacklist vulnerability in the `lxml.html.clean` module in lxml before 3.3.5 allows remote attackers to conduct cross-site scripting (XSS) attacks via control characters in the link scheme to the `clean_html` function.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/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" : [ {
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    },
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  }, {
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    "url" : "https://mailman-mail5.webfaction.com/pipermail/lxml/2014-April/007128.html"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20140724172044/http://secunia.com/advisories/58013"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20140805110535/http://secunia.com/advisories/59008"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20140806061046/http://secunia.com/advisories/58744"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20141017122607/https://mailman-mail5.webfaction.com/pipermail/lxml/2014-April/007128.html"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20150523055039/http://www.mandriva.com/en/support/security/advisories/advisory/MDVSA-2015:112/?name=MDVSA-2015:112"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20200228180542/http://www.securityfocus.com/bid/67159"
  }, {
    "type" : "WEB",
    "url" : "http://advisories.mageia.org/MGASA-2014-0218.html"
  }, {
    "type" : "WEB",
    "url" : "http://lists.opensuse.org/opensuse-updates/2014-05/msg00083.html"
  }, {
    "type" : "WEB",
    "url" : "http://lxml.de/3.3/changes-3.3.5.html"
  }, {
    "type" : "WEB",
    "url" : "http://seclists.org/fulldisclosure/2014/Apr/210"
  }, {
    "type" : "WEB",
    "url" : "http://seclists.org/fulldisclosure/2014/Apr/319"
  }, {
    "type" : "WEB",
    "url" : "http://www.debian.org/security/2014/dsa-2941"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2014/05/09/7"
  }, {
    "type" : "WEB",
    "url" : "http://www.ubuntu.com/usn/USN-2217-1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-08-04T20:12:48Z",
    "nvd_published_at" : "2014-05-14T19:55:00Z"
  }
}