CVE-2026-18140

High

Description

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductAmazon Aws-smithy-json

PublishedJul 30, 2026

First seenJul 30, 2026

Weakness typeCWE-674CWE-674

How to fix

Update

amazon aws-smithy-json0.62.7 or later

Patches

crates.io/crates/aws-smithy-json/0.62.7

Vendor advisories

aws.amazon.com/security/security-bulletins/2026-067-aws/

Affected products

Product	Affected versions	Fixed in
amazon aws-smithy-json	v < 0.62.7	0.62.7

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