GHSA-2r23-2g6v-2m5f CVE-2026-42999 PYSEC-2026-600

OpenStack Keystone has an Authorization Bypass

High PyPI

Severity: 6.0 / 10; High · CVSS 3.1
Exploit chance (EPSS): 0.33%; Chance of exploitation in the next 30 days. Higher than 26.12% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-639 Authorization Bypass Through User-Controlled Key; CWE-863 Incorrect Authorization
Fix: 27.0.2; Upgrade keystone to this version or later

Description

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).

Affected versions

PyPI

Package	Vulnerable	Fixed in
keystone	`>= 14.0.0, < 27.0.2`	`27.0.2`
keystone	`>= 28.0.0, < 28.0.2`	`28.0.2`
keystone	`>= 29.0.0, < 29.0.2`	`29.0.2`
keystone	`>= 14.0.0, < 27.0.2` `>= 28.0.0, < 28.0.2` `>= 29.0.0, < 29.0.2`	`27.0.2` `28.0.2` `29.0.2`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

keystone PyPI → `27.0.2`

pip

pip install --upgrade "keystone>=27.0.2"

poetry

poetry add "keystone>=27.0.2"

uv

uv add "keystone>=27.0.2"

Severity breakdown

CVSS 3.1 6.0

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L

Attack vector: Network
Attack complexity: High
Privileges required: Low
User interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: Low

Weakness

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 to prevent it

Architecture and Design: For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
Architecture and Design, Implementation: Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
Architecture and Design: Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.

CWE-863: Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

How to prevent it

Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

References

Advisories

Packages

github.com/openstack/keystone

Timeline

May 28, 2026 Published
Oct 26, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-whqr-fgm5-x77q OpenStack Keystone's federated token rescoping mechanism doesn't propagate the original token's expiry to the newly issued token	High	Also affects keystone
GHSA-q623-f4j4-p4xj OpenStack Keystone has an Incorrect Authorization issue	High	Also affects keystone
GHSA-8f8m-wrvr-wcvf OpenStack Keystone doesn't verify that the user supplied in the authentication request matches the owner of the application credential	High	Also affects keystone
GHSA-hhq2-3832-xxcv OpenStack Keystone has an Incorrect Authorization Issue	High	Also affects keystone
GHSA-pfx2-9x9m-7ghx OpenStack Keystone: LDAP identity backend does not convert enabled attribute to boolean	High	Also affects keystone
GHSA-4phw-6824-6cfp OpenStack Keystone: Restricted application credentials can create EC2 credentials	Medium	Also affects keystone
GHSA-hcqg-5g63-7j9h OpenStack Keystone allows /v3/ec2tokens or /v3/s3tokens request with valid AWS Signature to provide Keystone authorization.	High	Also affects keystone
GHSA-cc99-whm5-mmq3 Openstack Keystone Incorrect Authorization vulnerability	Critical	Also affects keystone

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