CVE-2026-49017: Openstack Swift

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Openstack Swift: from 2.35.1, before 2.35.3 (fixed in 2.35.3); from 2.36.0, before 2.36.2 (fixed in 2.36.2); from 2.37.0, before 2.37.2 (fixed in 2.37.2)

Published 2026-05-27. Last modified 2026-09-24.