Medium · published May 27, 2026
In OpenStack Swift before 2.36.2 and 2.37.2, s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body. The StreamingInput class repeatedly appends an empty buffer and re-reads, causing the proxy-server worker handling the request to become permanently unresponsive with increasing CPU and memory consumption. An authenticated attacker can systematically exhaust all proxy-server workers, resulting in denial of service. The defect was introduced in Swift 2.36.0.
| Product | Versions | Fixed in |
|---|---|---|
| openstack/swift | ≥ 2.35.1, < 2.35.3 | 2.35.3 |
| openstack/swift | ≥ 2.36.0, < 2.36.2 | 2.36.2 |
| openstack/swift | ≥ 2.37.0, < 2.37.2 | 2.37.2 |