This vulnerability in OpenStack Keystone prior to versions 26.0.1, 27.0.0, and 28.0.0 allows an attacker to use a valid AWS Signature in requests to the /v3/ec2tokens or /v3/s3tokens endpoints to obtain Keystone authorization improperly. The issue impacts the Heat project across many specific Ubuntu package versions. The vulnerability is identified by CVSS vector AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N, indicating network attack vector, high attack complexity, no privileges or user interaction required, with a scope change, low confidentiality impact, high integrity impact, and no availability impact.

An attacker with a valid AWS Signature can gain unauthorized Keystone authorization via the vulnerable endpoints, potentially allowing them to escalate privileges or perform unauthorized actions within the OpenStack environment. The vulnerability affects confidentiality and integrity but does not impact availability. There are no known exploits in the wild as of the published date.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Users should monitor vendor advisories for updates and apply official patches once available. Until then, restrict access to the vulnerable endpoints and validate AWS Signature usage carefully.