Cyber Resilience

CVE-2026-42998

Access Control in Openstack Keystone 14.0.0 – 27.0.2

Public PoCAccess Control
Published
28 May 2026
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:L
EPSS Score 0.0030 23th percentile
Risk Priority 43 floored blend · peak EPSS

Summary

CVE-2026-42998 is a medium-severity Incorrect Authorization (CWE-863) vulnerability in Openstack Keystone. Its CVSS base score is 6.0 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 23th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

No EU or UK CSIRT advisories indexed for this CVE.

Vulnerability Data

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…

more

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.

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
T1548.002 Bypass User Account Control Privilege Escalation
Adversaries may bypass UAC mechanisms to elevate process privileges on system.
attack.mitre.org →
T1548.003 Sudo and Sudo Caching Privilege Escalation
Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-44394Same product: Openstack Keystone
CVE-2026-33551Same product: Openstack Keystone
CVE-2026-42999Same product: Openstack Keystone
CVE-2026-43000Same product: Openstack Keystone
CVE-2026-43001Same product: Openstack Keystone
CVE-2024-39690Shared CWE-863
CVE-2023-1979Shared CWE-863
CVE-2024-10295Shared CWE-863
CVE-2026-41375Shared CWE-863
CVE-2024-39025Shared CWE-863

Affected Assets

openstack
keystone
14.0.0 — 27.0.2 · 28.0.0 — 28.0.2 · 29.0.0 — 29.0.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

AC-3 directly requires correct enforcement of authorization decisions on every access request, structurally preventing incorrect checks.

AC-24 Access Control Decisions good match

AC-24 ensures access-control decisions are made and applied consistently, reducing the chance of an incorrect authorization result.

AC-25 Reference Monitor good match

A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.

AC-6 Least Privilege partial match

Least-privilege assignments shrink the set of authorizations that must be checked correctly, limiting exposure to flawed checks.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.15 Access control partial match
prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

A.5.18 Access rights partial match
prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

A.8.3 Information access restriction partial match
prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863
RHEL 7 (1 rule)
  • V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863

References