Vulnerability PYSEC-2026-3080

Unknown

2 months ago

OpenStack Swift: s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body

2.36.0 - 2.36.1 and 2.37.0 - 2.37.1

Summary

OpenStack Swift: s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body

Details

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.