CVE-2026-18140

A flaw was found in aws-smithy-json. This vulnerability allows a remote, unauthenticated attacker to cause a denial of service (DoS) in smithy-rs generated servers. By sending a small HTTP request containing deeply nested JSON, the attacker can trigger uncontrolled recursion in the aws-smithy-json runtime, leading to stack exhaustion and a process abort. This can make the affected server unavailable to legitimate users.

This flaw in the aws-smithy-json runtime crate allows a remote unauthenticated attacker to trigger a denial of service by sending a crafted HTTP request with deeply nested JSON. Red Hat products utilizing smithy-rs generated servers, such as components in Red Hat Enterprise Linux and Red Hat Trusted Artifact Signer, are susceptible to service disruption if exposed to untrusted networks.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Restrict network access to services that process JSON input using the aws-smithy-json runtime. Configure firewalls to limit incoming connections to trusted sources, thereby reducing the exposure to remote unauthenticated denial of service attacks. If the service is reloaded or restarted, ensure firewall rules persist.