CVE-2016-4807: Web2py Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-pvcp-73cg-6f77
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CVSS 4.8
CWE-79
Published
Advisory Summary

CVE-2016-4807 is a MODERATE (CVSS 4.8) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Web2py libraries in the PyPI ecosystem. The issue involves web2py reflected xss vulnerability. Remediation is available in the latest vendor maintenance releases.

CVE-2016-4807 at a Glance

CVE Identifier CVE-2016-4807
GHSA Identifier GHSA-pvcp-73cg-6f77
Severity MODERATE
CVSS v3.1 Base Score 4.8
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Web2py
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 4.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required High (PR:H)
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-2016-4807

To remediate this vulnerability, upgrade all affected Web2py dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

web2py fixed: Latest secure release 
pip install web2py>=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 web2py

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2016-4807, inspect your installed packages using pip:

pip show web2py

Analyze the terminal output to locate any version of Web2py 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 web2py 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 Web2py, 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

Web2py versions 2.14.5 and below was affected by Reflected XSS vulnerability, which allows an attacker to perform an XSS attack on logged in user (admin).

CVE-2016-4807 Affected Web2py Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
web2py
pypi/web2py
PyPI
≤ 2.14.5

References

NVD — CVE-2016-4807 NVD
https://nvd.nist.gov/vuln/detail/CVE-2016-4807
Web2py Source Repository REPOSITORY
https://github.com/web2py/web2py
www.exploit-db.com/exploits/39821 WEB
https://www.exploit-db.com/exploits/39821
Web2py Security Information SECURITY
http://packetstormsecurity.com/files/137070/Web2py-2.14.5-CSRF-XSS-Local-File-Inclusion.html

Frequently Asked Questions

What is CVE-2016-4807?
CVE-2016-4807 is a security vulnerability in Web2py involving Web2py Reflected XSS vulnerability under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Web2py versions are affected?
Affected versions include releases prior to current release patches across affected packages: web2py.
What version fixes CVE-2016-4807?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is web2py affected?
Yes, web2py 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-2016-4807?
CVE-2016-4807 has a CVSS v3.1 base score of 4.8 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2016-4807?
CVE-2016-4807 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-2016-4807?
Run the dependency tree command: 'pip show web2py'. 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-pvcp-73cg-6f77",
  "modified" : "2025-04-21T22:52:15Z",
  "published" : "2022-05-17T03:05:11Z",
  "aliases" : [ "CVE-2016-4807" ],
  "summary" : "Web2py Reflected XSS vulnerability",
  "details" : "Web2py versions 2.14.5 and below was affected by Reflected XSS vulnerability, which allows an attacker to perform an XSS attack on logged in user (admin).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "web2py"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "2.14.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2016-4807"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/web2py/web2py"
  }, {
    "type" : "WEB",
    "url" : "https://www.exploit-db.com/exploits/39821"
  }, {
    "type" : "WEB",
    "url" : "http://packetstormsecurity.com/files/137070/Web2py-2.14.5-CSRF-XSS-Local-File-Inclusion.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-04-21T22:52:15Z",
    "nvd_published_at" : "2017-01-11T16:59:00Z"
  }
}