AWS Lambda Flaw Allows IAM Permission Bypass and Unauthorized Cloud Access
A critical authorization flaw in AWS's Amazon Connect Salesforce Lambda application enables attackers to bypass IAM permissions and execute privileged cloud operations.
Amazon Web Services (AWS) has disclosed a significant authorization vulnerability, tracked as CVE-2026-94384, within its Amazon Connect Salesforce Lambda application. This flaw resides in the sfExecuteAWSService Lambda function, present in versions 5.15 through 5.24.16 of the AmazonConnectSalesforceLambda application, which is designed to integrate Amazon Connect contact-center services with Salesforce.
The vulnerability arises because the sfExecuteAWSService function fails to adequately verify the authorization of the caller requesting specific AWS operations. Instead, it can forward parameters provided by the caller directly to AWS service APIs while utilizing its own elevated execution role. This mechanism effectively transforms the Lambda function into a privileged proxy, allowing any IAM principal with the lambda:InvokeFunction permission to potentially execute privileged AWS operations that their individual IAM policies would otherwise prohibit.
This permission-bypass condition creates a significant risk for organizations. An attacker who gains control of an IAM identity with the ability to invoke the vulnerable function could exploit this weakness to access sensitive AWS services, modify cloud resources without authorization, or perform actions dictated by the Lambda execution role's permissions. The ultimate impact is contingent upon the specific permissions granted to the function's role and the range of AWS APIs accessible through the function's parameters.
AWS has emphasized that the sfExecuteAWSService function is intended solely for the initial deployment and setup of the Amazon Connect and Salesforce integration. Organizations that leave this function enabled after the configuration process is complete may inadvertently create an accessible pathway for privilege escalation. This risk is particularly pronounced in environments where Lambda invocation permissions are broadly distributed among developers, automation accounts, third-party integrations, or other IAM principals.
To address CVE-2026-94384, AWS has released version 5.26 of the AmazonConnectSalesforceLambda application. Customers using impacted versions are strongly advised to upgrade to the latest version immediately. Furthermore, organizations should review the necessity of the sfExecuteAWSService function post-integration setup and consider disabling or deleting it if it is no longer required.
For organizations that must retain the function, AWS recommends implementing strict access controls. This includes limiting lambda:InvokeFunction access exclusively to the single IAM user designated for the CTI Adapter. No other IAM users, roles, groups, or principals should be granted invocation privileges. Enhanced security measures can be implemented using AWS Service Control Policies or permission boundaries to explicitly deny invocation access for all other principals.
Additionally, administrators should configure the SalesforceExecuteAWSServiceUser parameter to match the IAM user authorized to use the CTI Adapter, thereby restricting cross-account invocation. Security teams are urged to verify that the vulnerable function has been removed or disabled after setup. Comprehensive security audits should include checks of IAM policies, Lambda resource policies, execution roles, CloudTrail logs, and cross-account trust configurations to detect any unauthorized usage.
The vulnerability was reported through a coordinated vulnerability disclosure process by Chang Li of Xidian University. This incident underscores the ongoing importance of carefully managing permissions and the lifecycle of integration components in cloud environments.