CVE-2026-43000 — keystone
MEDIUMCVE-2026-43000 is a medium-severity (CVSS 6) CWE-863 vulnerability in keystone. A fix is available for keystone — see the affected versions and patch details below.
OpenStack Keystone has an Incorrect Authorization issue
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43000.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-43000 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 384,993 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
keystone🐍keystone🐍keystoneReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in OpenStack Keystone before 29.0.2. When combined with an application credential impersonation vulnerability, an attacker with the member role on a project can escalate to admin by chaining unrestricted application credentials with Keystone trusts. The impersonated token carries the victim's identity, which passes the trustor validation check. Keystone then validates the delegated roles against the victim's actual role assignments in the database, not the roles on the requesting token. This allows the attacker to create a trust delegating the victim's admin role to themselves. The trust persists independently, and additional trusts and application credentials can be created to maintain access. All actions are logged under the victim's identity.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | keystone | ≥ 14.0.0&&< 27.0.2 | 27.0.2pip install --upgrade 'keystone==27.0.2' |
| 🐍PyPI | keystone | ≥ 28.0.0&&< 28.0.2 | 28.0.2pip install --upgrade 'keystone==28.0.2' |
| 🐍PyPI | keystone | ≥ 29.0.0&&< 29.0.2 | 29.0.2pip install --upgrade 'keystone==29.0.2' |
Affected Products
keystoneopenstackDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for keystone, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update keystone to 27.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43000 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-43000 in your dependencies?
Find it across PyPI, including transitive dependencies.