CVE-2026-71191 Missing authorization in Swift
Attackers can read arbitrary objects via unsigned headers in presigned URLs, bypassing signature validation in OpenStack Swift S3API.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-71191?
CVE-2026-71191 is a medium-severity missing authorization vulnerability in OpenStack Swift, published on 5 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-863
Which versions are affected by CVE-2026-71191?
How do I fix CVE-2026-71191?
Apply the vendor's patch.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-71191 being exploited?
There is no known exploitation of CVE-2026-71191 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-71191, GHSA-hqwm-h3rj-hvcf, UBUNTU-CVE-2026-71191.