CVE-2026-42999: Keystone OpenStack Keystone Has An Authorization Vulnerability

MODERATE
Advisory Identifier: GHSA-2r23-2g6v-2m5f
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CVSS 6.0
CWE-639 CWE-863
Published
Advisory Summary

CVE-2026-42999 is a MODERATE (CVSS 6.0) openstack keystone has an authorization vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Keystone libraries in the PyPI ecosystem. The issue involves openstack keystone has an authorization bypass. Remediation is available by upgrading affected packages to version 27.0.2, 28.0.2, 29.0.2.

CVE-2026-42999 at a Glance

CVE Identifier CVE-2026-42999
GHSA Identifier GHSA-2r23-2g6v-2m5f
Severity MODERATE
CVSS v3.1 Base Score 6.0
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Keystone
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.0

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

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

How to Fix CVE-2026-42999

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: 27.0.2 
pip install keystone>=27.0.2
keystone fixed: 28.0.2 
pip install keystone>=28.0.2
keystone fixed: 29.0.2 
pip install keystone>=29.0.2
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-2026-42999, 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 27.0.2), 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-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. 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

An issue was discovered in OpenStack Keystone before 29.0.2. The Keystone RBAC policy enforcer in enforce_call unconditionally merges the raw JSON request body into the policy enforcement dictionary via policy_dict.update(json_input.copy()), overwriting trusted target data that was previously set from database lookups. Because flask.request.get_json is called with force=True, this works regardless of Content-Type or HTTP method. Any authenticated user can inject arbitrary policy target attributes (e.g., user_id, project_id) into the request body to bypass RBAC checks and perform unauthorized operations on resources belonging to other users or projects. This was introduced in commit 5ea59f52 (Rocky/14.0.0).

CVE-2026-42999 Affected Keystone Versions

3 component(s)
Fixed Versions:
27.0.228.0.229.0.2
Product / Package Ecosystem Affected Versions Fixed Version
keystone
pypi/keystone
PyPI
≥ 14.0.0
< 27.0.2
27.0.2
keystone
pypi/keystone
PyPI
≥ 28.0.0
< 28.0.2
28.0.2
keystone
pypi/keystone
PyPI
≥ 29.0.0
< 29.0.2
29.0.2

References

NVD — CVE-2026-42999 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42999
Keystone Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-42999
bugs.launchpad.net/keystone/+bug/21483... WEB
https://bugs.launchpad.net/keystone/+bug/2148398
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2482840
Keystone Source Repository REPOSITORY
https://github.com/openstack/keystone
Keystone Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/keystone/PYSEC-2026-600.yaml
Keystone Security Information SECURITY
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42999.json
Keystone Security Information SECURITY
https://security.openstack.org/ossa/OSSA-2026-015.html

Frequently Asked Questions

What is CVE-2026-42999?
CVE-2026-42999 is a security vulnerability in Keystone involving OpenStack Keystone has an Authorization Bypass under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Keystone versions are affected?
Affected versions include releases prior to 27.0.2, 28.0.2, 29.0.2 across affected packages: keystone.
What version fixes CVE-2026-42999?
Upgrading to 27.0.2, 28.0.2, 29.0.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is keystone affected?
Yes, keystone is affected in releases prior to 27.0.2, 28.0.2, 29.0.2. Upgrade your dependency to 27.0.2, 28.0.2, 29.0.2 or later.
What is the CVSS score of CVE-2026-42999?
CVE-2026-42999 has a CVSS v3.1 base score of 6.0 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L.
What CWE is associated with CVE-2026-42999?
CVE-2026-42999 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check PyPI dependencies for CVE-2026-42999?
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-2r23-2g6v-2m5f",
  "modified" : "2026-07-02T17:44:03Z",
  "published" : "2026-05-28T21:32:02Z",
  "aliases" : [ "CVE-2026-42999" ],
  "summary" : "OpenStack Keystone has an Authorization Bypass",
  "details" : "An issue was discovered in OpenStack Keystone before 29.0.2. The Keystone RBAC policy enforcer in enforce_call unconditionally merges the raw JSON request body into the policy enforcement dictionary via policy_dict.update(json_input.copy()), overwriting trusted target data that was previously set from database lookups. Because flask.request.get_json is called with force=True, this works regardless of Content-Type or HTTP method. Any authenticated user can inject arbitrary policy target attributes (e.g., user_id, project_id) into the request body to bypass RBAC checks and perform unauthorized operations on resources belonging to other users or projects. This was introduced in commit 5ea59f52 (Rocky/14.0.0).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "keystone"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "14.0.0"
      }, {
        "fixed" : "27.0.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "keystone"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "28.0.0"
      }, {
        "fixed" : "28.0.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "keystone"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "29.0.0"
      }, {
        "fixed" : "29.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42999"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-42999"
  }, {
    "type" : "WEB",
    "url" : "https://bugs.launchpad.net/keystone/+bug/2148398"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2482840"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openstack/keystone"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/keystone/PYSEC-2026-600.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42999.json"
  }, {
    "type" : "WEB",
    "url" : "https://security.openstack.org/ossa/OSSA-2026-015.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639", "CWE-863" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-02T17:44:03Z",
    "nvd_published_at" : "2026-05-28T19:16:37Z"
  }
}