CVE-2026-93861
Description
A flaw was found in OpenStack Mistral. An authenticated project that has been granted and accepted access to another project's private workflow can further delegate that access to a third, arbitrary project without the workflow owner's knowledge or consent. The unauthorized delegation succeeds because the membership creation endpoint does not verify that the requesting project is the actual owner of the workflow. This allows an attacker to grant read and execution access to private workflows to projects the owner never authorized, and because the spurious membership record is stored under the delegating project's identity rather than the owner's, the owner cannot see or revoke it.
Statement
Red Hat product impact analysis pending. Component mapping required to determine which products ship the affected code. OpenStack Mistral is shipped as part of Red Hat OpenStack Platform (RHOSP). Versions of RHOSP shipping Mistral versions <20.1.1, ==21.0.0, ==22.0.0, or ==23.0.0 are potentially affected. The vulnerability requires an authenticated OpenStack project that already holds an accepted workflow membership, so the attack surface is limited to deployments where the resource sharing feature is in use and authentication is enabled.
Mitigation
No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.4 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | Low | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Red Hat CVSS v3 Score Explanation
Network REST API, low-privilege authenticated member can create unauthorized memberships; confidentiality and integrity limited to workflow definitions and sharing state
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
An attacker could read sensitive data, either by reading the data directly from a data store that is not restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity
Technical Impact: Modify Application Data; Modify Files or Directories
An attacker could modify sensitive data, either by writing the data directly to a data store that is not restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control
Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism
An attacker could gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An attacker could gain unauthorized access to resources on the system and excessively consume those resources, leading to a denial of service.
Acknowledgements
Upstream acknowledges Chen YuXiang (Institute of Computing Technology, Chinese Academy of Sciences) as the original reporter.
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