CVE-2026-71191

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-08-05 06:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-24 15:10 UTC Last updatedMost recent change to the record

Details

Published

2026-08-05 06:16 UTC

Last modified

2026-10-24 15:10 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-863 · Incorrect authorization

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 6.0

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

High

Integrity

None

Availability

None