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CVE-2026-18140GHSA-8ffr-xgwf-xj56

aws-smithy-json: Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated remote denial of service in smithy-rs generated servers

AWS aws-smithy-jsonrustContainers & cloud
Open in ThreatlineRecord JSON
CVSS
8.7High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.43%Chance of exploitation activity in the next 30 days, higher than 36% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in0.62.7Fixed versionGitHub
Published30 Jul 2026Updated 2 Oct 2026CVE List

What fixes it

  • 0.62.7aws-smithy-json, rustGitHub
  • 0.62.7aws-smithy-json, crates.ioOSVcargo update -p aws-smithy-json --precise 0.62.7

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

Summary

Smithy-RS is a Rust code generation and runtime framework that generates HTTP clients and servers from Smithy interface definitions, powering the AWS SDK for Rust and custom service implementations. An issue exists which allows uncontrolled recursion in the unknown-key skip path of the Amazon aws-smithy-json runtime crate in versions 0.62.6 and earlier.

Impact

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.

Impacted versions: aws-smithy-json <= 0.62.6

Patches

This issue has been addressed in aws-smithy-json version 0.62.7. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds

There are no workarounds besides updating to the patched version.

References

If you have any questions or comments about this advisory, AWS asks that you contact [AWS/Amazon] Security via their vulnerability reporting page or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.

Text from GitHub Advisory Database

Affected versions 3

  • aws-smithy-json, rust<= 0.62.6GitHub
  • aws-smithy-jsonaffected: 0.32.0 through 0.62.6CVE List
  • aws-smithy-json, crates.iofrom first release, fixed in 0.62.7OSV

References 8