Vulnerability Description
In OpenStack Swift through 2.38.0, S3API middleware does not enforce that semantic x-amz-* headers are covered by the SigV4 signature on presigned URL requests. An attacker who obtains a presigned PUT URL can inject an unsigned X-Amz-Copy-Source header, causing Swift to perform a server-side copy from an arbitrary source object using the signer's authorization context. The attacker can read any object the signer has access to, provided the target project_id, container name, and object name are known. This affects all deployments using the default s3_acl=false configuration.
Related Weaknesses (CWE)
References
- https://launchpad.net/bugs/2158733
- https://openwall.com/lists/oss-security/2026/07/28/26
- https://security.openstack.org/ossa/OSSA-2026-030.html
FAQ
What is CVE-2026-71191?
CVE-2026-71191 is a documented vulnerability. In OpenStack Swift through 2.38.0, S3API middleware does not enforce that semantic x-amz-* headers are covered by the SigV4 signature on presigned URL requests. An attacker who obtains a presigned PUT...
How severe is CVE-2026-71191?
CVSS scoring is not yet available for CVE-2026-71191. Check NVD for updates.
Is there a patch for CVE-2026-71191?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.