CVE-2026-42998

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.

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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

0.0030

Probability of exploitation

0.21%

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-2026-42998? +

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

How severe is CVE-2026-42998? +

CVE-2026-42998 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 0.0030, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-42998? +

CVE-2026-42998 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-2026-42998? +

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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