---
title: "CVE-2026-42998\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-42998?format=md
keywords: index, follow
---

# CVE-2026-42998

Publication date 28 May 2026

Last updated 18 June 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**6.0 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2026-42998?format=md#impact-score)

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## Description

An issue was discovered in OpenStack Keystone before 29.0.2. The Keystone
application credential authentication plugin does not verify that the user
supplied in the authentication request matches the owner of the application
credential. An attacker can authenticate with their own application
credential ID and secret while specifying a different user's name and
domain in the request body. Keystone issues a token attributed to the
victim user. The impersonated token is project-scoped and carries the
intersection of the application credential's roles and the victim's actual
roles on the project. This enables audit evasion, reading the victim's
credentials, and acting as the victim within shared projects.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| keystone | 26.04 LTS resolute | Fixed 2:29.0.0-0ubuntu1.2 |
| 25.10 questing | Fixed 2:28.0.0-0ubuntu1.3 |
| 24.04 LTS noble | Fixed 2:25.0.0-0ubuntu1.4 |
| 22.04 LTS jammy | Fixed 2:21.0.1-0ubuntu2.4 |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

6.0 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | High |
  | Privileges required | Low |
  | User interaction | None |
  | Scope | Changed |
  | Confidentiality impact | Low |
  | Integrity impact | Low |
  | Availability impact | Low |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.0 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-42998)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-42998)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-42998)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-42998)

### Related Ubuntu Security Notices (USN)

+ [USN-8433-1](https://usn.ubuntu.com/USN-8433-1)
+ OpenStack Keystone vulnerabilities
+ 16 June 2026

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-42998>
* <https://bugs.launchpad.net/keystone/+bug/2148477>
* <https://security.openstack.org/ossa/OSSA-2026-015.html>