CVE-2026-71191: CWE-863 Incorrect Authorization in OpenStack Swift
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.
AI Analysis
Technical Summary
CVE-2026-71191 describes an incorrect authorization vulnerability (CWE-863) in OpenStack Swift's S3API middleware up to version 2.38.0. The issue arises because semantic x-amz-* headers are not enforced to be included in the SigV4 signature on presigned URL requests. An attacker who obtains a presigned PUT URL can exploit this by injecting an unsigned X-Amz-Copy-Source header, triggering a server-side copy operation from an arbitrary source object within the signer's authorization scope. This enables unauthorized reading of objects if the attacker knows the target project_id, container name, and object name. The vulnerability affects all deployments with the default s3_acl=false setting. The CVSS 4.0 score is 6.0 (medium severity). The product is a cloud service, and the vendor manages remediation server-side. A patch is available.
Potential Impact
An attacker with a presigned PUT URL can perform unauthorized server-side copy operations to read objects that the signer has access to, bypassing intended authorization controls. This can lead to unauthorized data disclosure within the affected OpenStack Swift deployments configured with s3_acl=false. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Since OpenStack Swift is a cloud service, the vendor manages remediation server-side. A patch is available for this vulnerability. Users should verify with the vendor advisory that their deployment has been updated to a fixed version or that the cloud service has been patched. No additional user action is required if the service is managed by the vendor and patched accordingly.
CVE-2026-71191: CWE-863 Incorrect Authorization in OpenStack Swift
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.
CVSS v4.0
Score 6.0medium
Affected software
OpenStack
Swift
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-71191 describes an incorrect authorization vulnerability (CWE-863) in OpenStack Swift's S3API middleware up to version 2.38.0. The issue arises because semantic x-amz-* headers are not enforced to be included in the SigV4 signature on presigned URL requests. An attacker who obtains a presigned PUT URL can exploit this by injecting an unsigned X-Amz-Copy-Source header, triggering a server-side copy operation from an arbitrary source object within the signer's authorization scope. This enables unauthorized reading of objects if the attacker knows the target project_id, container name, and object name. The vulnerability affects all deployments with the default s3_acl=false setting. The CVSS 4.0 score is 6.0 (medium severity). The product is a cloud service, and the vendor manages remediation server-side. A patch is available.
Potential Impact
An attacker with a presigned PUT URL can perform unauthorized server-side copy operations to read objects that the signer has access to, bypassing intended authorization controls. This can lead to unauthorized data disclosure within the affected OpenStack Swift deployments configured with s3_acl=false. No known exploits are reported in the wild at this time.
Mitigation Recommendations
Since OpenStack Swift is a cloud service, the vendor manages remediation server-side. A patch is available for this vulnerability. Users should verify with the vendor advisory that their deployment has been updated to a fixed version or that the cloud service has been patched. No additional user action is required if the service is managed by the vendor and patched accordingly.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-08-05T05:01:20.566Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Is Cloud Service
- true
Threat ID: 6a72cd1fbf8831d5394f40e7
Added to database: 08/05/2026, 05:41:51 UTC
Last enriched: 08/12/2026, 15:02:55 UTC
Last updated: 09/18/2026, 22:01:37 UTC
Views: 51
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