# CVE-2026-15957: Uncontrolled recursion in smithy-rs generated JSON, CBOR, and XML deserializers allows unauthenticated remote denial of service via recursive shapes

> CVE-2026-15957: Uncontrolled recursion in smithy-rs generated JSON, CBOR, and XML deserializers allows unauthenticated remote denial of service via recursive shapes. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-15957
Last updated: 2026-10-24T19:10:00Z

- Published: 2026-07-21 19:33 UTC · Updated: 2026-10-24 19:10 UTC · Assigner: AMZN
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 0.75%, 55th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-674

## Description

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. Uncontrolled recursion in the JSON, CBOR, and XML deserializer functions emitted by Amazon smithy-rs code generation could allow remote attackers to cause a denial of service (process abort via stack exhaustion) via a small request containing deeply nested data for a recursive model shape to a generated SDK or server. To mitigate this issue, users should upgrade to aws-sdk-rust release-2026-06-02 or later. Users building custom servers with smithy-rs codegen should regenerate from smithy-rs release-2026-06-01 or later.

## Affected vendors and products

- AWS: aws-sdk-rust

## Tracked companies

- [Amazon Web Services](https://rewindex.com/company/aws.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-15957)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-15957)
- [https://aws.amazon.com/security/security-bulletins/2026-061-aws/](https://aws.amazon.com/security/security-bulletins/2026-061-aws/)
- [https://github.com/awslabs/aws-sdk-rust/releases/tag/release-2026-06-02](https://github.com/awslabs/aws-sdk-rust/releases/tag/release-2026-06-02)
- [https://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-4f2p-7j38-4xrg](https://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-4f2p-7j38-4xrg)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-15957 · Markdown: https://rewindex.com/cve/CVE-2026-15957.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-15957 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:11:26.026Z