CVE-2026-71191
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.
CSIRTS triage
- What
- Swift distributed virtual object store contains SSRF vulnerability and s3api middleware authorization bypass.
- Who is affected
- Deployments using Swift object store, especially those using s3api middleware.
- Urgency
- High urgency due to authorization bypass and information disclosure via SSRF.
- Action
- Apply DSA-6449-1 security update to Swift.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 17% of all EPSS-scored CVEs.
Advisory coverage (2)
- unknownDSA-6449-1 swift - security updatedebian · 2026-08-18
- unknownCVE-2026-71191: In OpenStack Swift through 2.38.0, S3API middleware does not enforce that semantic x-amz-* hea…nvd · 2026-08-05
External references
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[](https://www.csirts.com/cve/CVE-2026-71191)