CVE-2026-43000

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-28 · updated 2026-10-26
Weakness: CWE-863

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 products

OpenStack Keystone: from 14.0.0 before 27.0.2; from 28.0.0 before 28.0.2; from 29.0.0 before 29.0.2 — fixed in 27.0.2, 28.0.2, 29.0.2

How to fix

Upgrade to a fixed version: OpenStack Keystone 27.0.2, 28.0.2, 29.0.2. Check the vendor advisory for mitigations.

References

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