AmazonAnalysisAWS patches Nitro Enclaves SDK use-after-free and KMS spoofing flaws
What happened.Amazon Web Services published security bulletin AWS-2026-157 addressing high-severity memory corruption and input validation vulnerabilities within the open-source AWS Nitro Enclaves SDK for C.
Why it matters.Confidential computing models isolate cryptographic operations and sensitive workloads from parent hypervisors and hosting environments. When inter-process communication interfaces permit memory corruption across vsock boundaries, enclave isolation assumptions collapse. Engineering organizations running confidential computing instances must rebuild enclave container images using SDK version 0.4.6. Developers should verify that KMS certificate validation rules reject spoofed regional endpoints.
The technical specifications:
- Vulnerability mechanics: Tracked as CVE-2026-119116 and CVE-2026-119148, the flaws involve a use-after-free condition in the kmstool-enclave command handler and missing validation on caller-supplied region strings.
- Exploitation path: Adversaries with execution rights on parent EC2 instances transmit crafted vsock packets to trigger heap corruption inside target enclaves, or spoof KMS server endpoints to inject actor-controlled keys.
- Remediation releases: AWS released Nitro Enclaves SDK version 0.4.6, correcting memory management routines and validating KMS endpoint hostnames to isolate enclave execution contexts.
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