Description
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.
Problem types
CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
Product status
2.36.0 (semver) before 2.36.2
2.37.0 (semver) before 2.37.2
2.35.1 (semver) before 2.35.3
References
www.openwall.com/lists/oss-security/2026/05/27/9
www.openwall.com/lists/oss-security/2026/06/02/6
bugs.launchpad.net/bugs/2152205
review.opendev.org/c/openstack/swift/+/987957
review.opendev.org/c/openstack/swift/+/988093