CVE-2026-15957: CWE-770 Allocation of resources without limits or throttling in AWS aws-sdk-rust
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.
AI Analysis
Technical Summary
Smithy-RS, the Rust code generation and runtime framework used by AWS SDK for Rust, generates deserializer functions for JSON, CBOR, and XML. These functions do not limit recursion depth, allowing an attacker to send a small request with deeply nested data for a recursive model shape, causing stack exhaustion and process abort (denial of service). This vulnerability is tracked as CVE-2026-15957 with a CVSS 3.1 score of 7.5 (high). AWS has addressed the issue in aws-sdk-rust release 2026-06-02 and smithy-rs release 2026-06-01 for custom server code generation.
Potential Impact
An attacker can cause a denial of service by sending a crafted request with deeply nested recursive data to an affected aws-sdk-rust client or server, leading to process termination due to stack exhaustion. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
A patch is available. Users should upgrade aws-sdk-rust to version 2026-06-02 or later. For custom servers built with smithy-rs code generation, regenerate code using smithy-rs release 2026-06-01 or later. Since this is a cloud service, AWS manages remediation for the cloud-hosted service; users should verify they are using updated SDK versions. Refer to the official AWS advisory at https://aws.amazon.com/security/security-bulletins/2026-061-aws/ for detailed guidance.
CVE-2026-15957: CWE-770 Allocation of resources without limits or throttling in AWS aws-sdk-rust
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.
CVSS v3.1
Score 7.5high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Smithy-RS, the Rust code generation and runtime framework used by AWS SDK for Rust, generates deserializer functions for JSON, CBOR, and XML. These functions do not limit recursion depth, allowing an attacker to send a small request with deeply nested data for a recursive model shape, causing stack exhaustion and process abort (denial of service). This vulnerability is tracked as CVE-2026-15957 with a CVSS 3.1 score of 7.5 (high). AWS has addressed the issue in aws-sdk-rust release 2026-06-02 and smithy-rs release 2026-06-01 for custom server code generation.
Potential Impact
An attacker can cause a denial of service by sending a crafted request with deeply nested recursive data to an affected aws-sdk-rust client or server, leading to process termination due to stack exhaustion. There is no impact on confidentiality or integrity reported.
Mitigation Recommendations
A patch is available. Users should upgrade aws-sdk-rust to version 2026-06-02 or later. For custom servers built with smithy-rs code generation, regenerate code using smithy-rs release 2026-06-01 or later. Since this is a cloud service, AWS manages remediation for the cloud-hosted service; users should verify they are using updated SDK versions. Refer to the official AWS advisory at https://aws.amazon.com/security/security-bulletins/2026-061-aws/ for detailed guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- AMZN
- Date Reserved
- 2026-07-16T13:52:17.532Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Is Cloud Service
- true
- Vendor Advisory Urls
- [{"url":"https://aws.amazon.com/security/security-bulletins/2026-061-aws/","vendor":"AWS"}]
Threat ID: 6a5fcbb52a4a8d5989ac6cb6
Added to database: 07/21/2026, 19:42:45 UTC
Last enriched: 07/21/2026, 19:50:38 UTC
Last updated: 07/21/2026, 21:09:10 UTC
Views: 4
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