CVE-2020-19002: Mezzanine Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-fpv7-hx6r-9vcx
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2020-19002 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Mezzanine libraries in the PyPI ecosystem. The issue involves mezzanine cross site scripting (xss) vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2020-19002 at a Glance

CVE Identifier CVE-2020-19002
GHSA Identifier GHSA-fpv7-hx6r-9vcx
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 Mezzanine
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-2020-19002

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

Mezzanine fixed: Latest secure release 
pip install Mezzanine>=Latest secure release
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 Mezzanine

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2020-19002, inspect your installed packages using pip:

pip show Mezzanine

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

Note: The pip show Mezzanine 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 Mezzanine, 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

Cross Site Scripting (XSS) in Mezzanine v4.3.1 allows remote attackers to execute arbitrary code via the `Description` field of the component `admin/blog/blogpost/add/`. This issue is different than CVE-2018-16632.

CVE-2020-19002 Affected Mezzanine Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
Mezzanine
pypi/Mezzanine
PyPI
≤ 6.0.0

References

NVD — CVE-2020-19002 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-19002
Mezzanine Source Repository REPOSITORY
https://github.com/stephenmcd/mezzanine/issues/1921
Mezzanine Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/mezzanine/PYSEC-2021-343.yaml
Mezzanine Source Repository REPOSITORY
https://github.com/stephenmcd/mezzanine
Mezzanine Source Repository REPOSITORY
https://github.com/stephenmcd/mezzanine/blob/v6.0.0/mezzanine/blog/templates/blog/blog_post_list.html#L112

Frequently Asked Questions

What is CVE-2020-19002?
CVE-2020-19002 is a security vulnerability in Mezzanine involving Mezzanine Cross Site Scripting (XSS) vulnerability under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Mezzanine versions are affected?
Affected versions include releases prior to current release patches across affected packages: Mezzanine.
What version fixes CVE-2020-19002?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is Mezzanine affected?
Yes, Mezzanine is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-19002?
CVE-2020-19002 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-2020-19002?
CVE-2020-19002 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-2020-19002?
Run the dependency tree command: 'pip show Mezzanine'. 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-fpv7-hx6r-9vcx",
  "modified" : "2026-06-10T18:45:51Z",
  "published" : "2022-05-24T19:12:23Z",
  "aliases" : [ "CVE-2020-19002" ],
  "summary" : "Mezzanine Cross Site Scripting (XSS) vulnerability",
  "details" : "Cross Site Scripting (XSS) in Mezzanine v4.3.1 allows remote attackers to execute arbitrary code via the `Description` field of the component `admin/blog/blogpost/add/`. This issue is different than CVE-2018-16632.",
  "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:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "Mezzanine"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "6.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-19002"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/stephenmcd/mezzanine/issues/1921"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/mezzanine/PYSEC-2021-343.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/stephenmcd/mezzanine"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/stephenmcd/mezzanine/blob/v6.0.0/mezzanine/blog/templates/blog/blog_post_list.html#L112"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-29T14:27:01Z",
    "nvd_published_at" : "2021-08-27T19:15:00Z"
  }
}