# CVE-2026-42999: OpenStack Keystone has an Authorization Bypass

> Authenticated users can bypass RBAC checks by injecting policy attributes into request bodies, allowing unauthorized access to other users' resources.

- **Severity:** Medium 6.0 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 May 2026
- **Updated:** 24 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-42999, GHSA-2r23-2g6v-2m5f, PYSEC-2026-600, UBUNTU-CVE-2026-42999, USN-8433-1

## What is CVE-2026-42999?

CVE-2026-42999 is a medium-severity missing authorization vulnerability in OpenStack Keystone, published on 28 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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).

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key), CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-42999?

7 open source packages ship an affected version, including keystone. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `keystone` | PyPI | From 14.0.0 | 27.0.2, 28.0.2, 29.0.2 |
| `keystone` | PyPI | From 14.0.0 | 27.0.2 |
| `keystone` | PyPI | From 14.0.0 | 27.0.2 |
| `keystone` | PyPI | From 28.0.0 | 28.0.2 |
| `keystone` | PyPI | From 28.0.0 | 28.0.2 |
| `keystone` | PyPI | From 29.0.0 | 29.0.2 |
| `keystone` | PyPI | From 29.0.0 | 29.0.2 |

Products: Openstack Keystone.

## How do I fix CVE-2026-42999?

Upgrade keystone to a fixed version for your release line: 27.0.2, 28.0.2 or 29.0.2.

## Is CVE-2026-42999 being exploited?

There is no known exploitation of CVE-2026-42999 in the wild and no public exploit code.

## Other vulnerabilities in OpenStack Keystone

- [CVE-2020-12690](https://insights.sbomify.com/CVE-2020-12690/): Insufficient Session Expiration in OpenStack Keystone (high 8.8)
- [CVE-2019-19687](https://insights.sbomify.com/CVE-2019-19687/): OpenStack Keystone Credential Leakage (high 8.8)
- [CVE-2026-43001](https://insights.sbomify.com/CVE-2026-43001/): OpenStack Keystone has an Incorrect Authorization Issue (high 7.9)
- [CVE-2014-2828](https://insights.sbomify.com/CVE-2014-2828/): OpenStack Identity (Keystone) DoS through V3 API authentication chaining (high 7.8)
- [CVE-2021-38155](https://insights.sbomify.com/CVE-2021-38155/): OpenStack Keystone allows information disclosure during account locking (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42999 and fix it if it is affected.

What it is: CVE-2026-42999 is a medium-severity missing authorization vulnerability in OpenStack Keystone, published on 28 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42999 in the wild and no public exploit code.

Affected packages and fixed versions:
- keystone (PyPI): affected from 14.0.0; fixed in 27.0.2, 28.0.2, 29.0.2
- keystone (PyPI): affected from 14.0.0; fixed in 27.0.2
- keystone (PyPI): affected from 14.0.0; fixed in 27.0.2
- keystone (PyPI): affected from 28.0.0; fixed in 28.0.2
- keystone (PyPI): affected from 28.0.0; fixed in 28.0.2
- keystone (PyPI): affected from 29.0.0; fixed in 29.0.2
- keystone (PyPI): affected from 29.0.0; fixed in 29.0.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42999/ (Markdown: https://insights.sbomify.com/CVE-2026-42999/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42999
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42999
- OSV: https://osv.dev/vulnerability/CVE-2026-42999

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42999/
Summaries are generated and may contain mistakes; the official description above is the record.