CVE-2026-18140: Amazon Aws-Smithy-JSON

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Uncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deserializer, might allow remote unauthenticated users to cause a denial of service (process abort via stack exhaustion) via a single small HTTP request containing deeply nested JSON to a smithy-rs generated server. To remediate this issue, users should upgrade to aws-smithy-json 0.62.7 or later and rebuild.

Affected products

• Amazon Aws-Smithy-JSON: before 0.62.7 (fixed in 0.62.7)

Published 2026-07-30. Last modified 2026-08-10.