CVE-2026-18140

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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.8% chance of exploitation in the next 30 days; higher than 55% of CVEs (scores of 2026-10-25)

CWE

CWE-674

Published

2026-07-30

Modified

2026-10-23

Record from

the NVD, synced 2026-10-24

Affected

• amazon:aws-smithy-json

Packages (OSV)

References

• https://aws.amazon.com/security/security-bulletins/2026-067-aws/
• https://crates.io/crates/aws-smithy-json/0.62.7
• https://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-8ffr-xgwf-xj56

Check your stackJSON