CVE-2026-43000

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.

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CVSS v3.1 Score

6.0

MEDIUM

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

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-863 Incorrect Authorization

Affected Products

Vendor	Product	Versions
openstack	keystone	14.0.0 — 27.0.2
openstack	keystone	28.0.0 — 28.0.2
openstack	keystone	29.0.0 — 29.0.2

References

Advisories & Patches

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

Exploits

https://bugs.launchpad.net/keystone/+bug/2148477

Frequently Asked Questions

What is CVE-2026-43000? +

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. It has a CVSS v3.1 base score of 6.0 (MEDIUM).

How severe is CVE-2026-43000? +

CVE-2026-43000 has a CVSS v3.1 score of 6.0 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-43000? +

CVE-2026-43000 affects products from openstack, specifically: keystone. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-43000? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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