CVE-2016-4911: Keystone OpenStack Identity Keystone Improper Access Vulnerability

MODERATE
Advisory Identifier: GHSA-f82m-w3p3-cgp3
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CVSS 4.3
CWE-284
Published
Advisory Summary

CVE-2016-4911 is a MODERATE (CVSS 4.3) openstack identity keystone improper access vulnerability (CWE-284: Improper Access Control) affecting Keystone libraries in the PyPI ecosystem. The issue involves openstack identity keystone improper access control. Remediation is available by upgrading affected packages to version 9.0.1.

CVE-2016-4911 at a Glance

CVE Identifier CVE-2016-4911
GHSA Identifier GHSA-f82m-w3p3-cgp3
Severity MODERATE
CVSS v3.1 Base Score 4.3
CWE Classification CWE-284: Improper Access Control
Affected Product Keystone
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 4.3

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

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

How to Fix CVE-2016-4911

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

keystone fixed: 9.0.1 
pip install keystone>=9.0.1
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 keystone

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2016-4911, inspect your installed packages using pip:

pip show keystone

Analyze the terminal output to locate any version of Keystone in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 9.0.1), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-284: Improper Access Control, where the product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. In Keystone, 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

The Fernet Token Provider in OpenStack Identity (Keystone) 9.0.x before 9.0.1 (mitaka) allows remote authenticated users to prevent revocation of a chain of tokens and bypass intended access restrictions by rescoping a token.

CVE-2016-4911 Affected Keystone Versions

1 component(s)
Fixed Versions:
9.0.1
Product / Package Ecosystem Affected Versions Fixed Version
keystone
pypi/keystone
PyPI
≥ 9.0.0
< 9.0.1
9.0.1

References

NVD — CVE-2016-4911 NVD
https://nvd.nist.gov/vuln/detail/CVE-2016-4911
Security Fix Commit FIX COMMIT
https://github.com/openstack/keystone/commit/0d376025bae61bf5ee19d992c7f336b99ac69240
Security Fix Commit FIX COMMIT
https://github.com/openstack/keystone/commit/ee1dc941042d1f71699971c5c30566af1b348572
bugs.launchpad.net/keystone/+bug/15775... WEB
https://bugs.launchpad.net/keystone/+bug/1577558
Keystone Source Repository REPOSITORY
https://github.com/openstack/keystone
Keystone Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/keystone/PYSEC-2016-38.yaml
review.openstack.org/ WEB
https://review.openstack.org/#/c/311886
Keystone Security Information SECURITY
https://security.openstack.org/ossa/OSSA-2016-008.html
Keystone Security Information SECURITY
http://www.openwall.com/lists/oss-security/2016/05/17/10
Keystone Security Information SECURITY
http://www.openwall.com/lists/oss-security/2016/05/17/11

Frequently Asked Questions

What is CVE-2016-4911?
CVE-2016-4911 is a security vulnerability in Keystone involving OpenStack Identity Keystone Improper Access Control under CWE-284: Improper Access Control.
Which Keystone versions are affected?
Affected versions include releases prior to 9.0.1 across affected packages: keystone.
What version fixes CVE-2016-4911?
Upgrading to 9.0.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is keystone affected?
Yes, keystone is affected in releases prior to 9.0.1. Upgrade your dependency to 9.0.1 or later.
What is the CVSS score of CVE-2016-4911?
CVE-2016-4911 has a CVSS v3.1 base score of 4.3 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2016-4911?
CVE-2016-4911 is classified under CWE-284: Improper Access Control (The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.).
How can I check PyPI dependencies for CVE-2016-4911?
Run the dependency tree command: 'pip show keystone'. 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-f82m-w3p3-cgp3",
  "modified" : "2024-11-26T18:27:07Z",
  "published" : "2022-05-17T03:41:03Z",
  "aliases" : [ "CVE-2016-4911" ],
  "summary" : "OpenStack Identity Keystone Improper Access Control ",
  "details" : "The Fernet Token Provider in OpenStack Identity (Keystone) 9.0.x before 9.0.1 (mitaka) allows remote authenticated users to prevent revocation of a chain of tokens and bypass intended access restrictions by rescoping a token.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "keystone"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.0.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2016-4911"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openstack/keystone/commit/0d376025bae61bf5ee19d992c7f336b99ac69240"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openstack/keystone/commit/ee1dc941042d1f71699971c5c30566af1b348572"
  }, {
    "type" : "WEB",
    "url" : "https://bugs.launchpad.net/keystone/+bug/1577558"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openstack/keystone"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/keystone/PYSEC-2016-38.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://review.openstack.org/#/c/311886"
  }, {
    "type" : "WEB",
    "url" : "https://security.openstack.org/ossa/OSSA-2016-008.html"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2016/05/17/10"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2016/05/17/11"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-05-14T21:05:37Z",
    "nvd_published_at" : "2016-06-13T14:59:00Z"
  }
}