CVE-2026-18140
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Other)
If parsed, recursive entity references allow the attacker to expand data exponentially, quickly consuming all system resources.
Frequently Asked Questions
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