Issues in AWS Nitro Enclaves SDK for C

Bulletin ID: 2026-157-AWS Publication Date: 10/30/2026 09:00 AM PDT Description: We identified CVE-2026-119116, a use-after-free in the SetClient command handler of the kmstool-enclave example application, where an application that executes on the parent EC2 instance could send crafted messages over vsock to corrupt heap memory inside the enclave and execute arbitrary code within it. Only enclave images that include kmstool-enclave, or code derived from it, are affected. We also identified CVE-2026-119148, an input validation issue in the SDK library where the AWS KMS server name is built from a caller-supplied region string. A third party could supply a crafted region to impersonate KMS to the enclave and inject forged responses, such as actor-chosen key material. Impacted versions: aws-nitro-enclaves-sdk-c <= v0.4.5 (CVE-2026-119116 affects kmstool-enclave only; CVE-2026-119148 affects the library) Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin. Read this article