CVE-2026-54382 in VitaFit
Summary
by MITRE • 11/04/2026
VitaFit cloud API before 2026-10-30 contained an improper access control vulnerability in its Cognito-issued AWS role that allows authenticated attackers to perform s3:PutObject operations across the entire shared bucket instead of being restricted to their own folder. Attackers can overwrite other users' objects in the shared S3 bucket using credentials obtained via CVE-2026-54378, destroying original content without triggering deletion protections.
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified in VitaFit cloud API prior to October 30, 2026, represents a critical failure in identity and access management within an Amazon Web Services S3 environment. This flaw is classified as Improper Access Control, aligning with CWE-269, which addresses situations where an actor can act outside of their intended permissions. The core technical issue lies in the configuration or issuance logic of AWS roles authenticated via Cognito. Instead of enforcing strict scoping policies that restrict each user's credentials to a specific directory path within a shared S3 bucket, the system issued IAM role credentials with overly permissive actions. Specifically, these credentials granted s3:PutObject permissions at the bucket level rather than the object or folder level. This architectural oversight means that any authenticated user possessing valid Cognito tokens could interact with the entire storage container as if they were an administrator of that specific bucket section, bypassing standard multi-tenant isolation boundaries.
The operational impact of this vulnerability is severe due to its potential for data integrity compromise and denial of service through destruction. Because the access control mechanism failed to validate the target path against the user's assigned identity scope, attackers could overwrite files belonging to other tenants or system components. The description notes that original content was destroyed without triggering deletion protections, indicating a lack of versioning safeguards or object lock mechanisms that might have otherwise preserved historical data states. This capability allows for silent corruption of critical application data, configuration files, or user-uploaded assets. In a multi-tenant SaaS environment, such an action not only disrupts the availability and integrity of services for legitimate users but also constitutes a significant breach of confidentiality if sensitive information stored in those objects is exposed through manipulation or subsequent access patterns enabled by the compromised state.
The exploitation vector relies on the combination of this improper access control with credential acquisition methods detailed in CVE-2026-54378. This suggests that while the S3 permissions were overly broad, they required initial authentication which was potentially vulnerable to other flaws such as session hijacking, token forgery, or identity provider misconfigurations. Once an attacker obtains valid credentials through these auxiliary vulnerabilities, the lack of granular resource-level policies in the IAM role allows for immediate lateral movement within the storage layer. From a threat modeling perspective using MITRE ATT&CK frameworks, this behavior maps to T1530 Data from Cloud Storage Object and potentially T1489 Service Stop if the overwriting is intended to disrupt service availability. The ability to overwrite objects without triggering deletion alerts also hints at a potential evasion of audit logging or monitoring systems that might rely on delete events rather than put events for anomaly detection, further complicating incident response efforts.
Mitigation strategies must focus on implementing strict least-privilege principles and enforcing resource-level permissions in AWS IAM policies. The immediate remediation involves updating the Cognito identity pool roles to include condition keys such as aws:ResourceTag or s3:prefix to ensure that put operations are restricted exclusively to paths corresponding to the authenticated user's unique identifier. For example, a policy should explicitly deny any action not matching the pattern /users/${cognito-identity.amazonaws.com:sub}/* and allow only actions within that specific prefix. Additionally, enabling S3 Bucket Versioning is critical to recover from accidental or malicious overwrites, providing an audit trail of changes and allowing restoration of previous object states. Implementing AWS CloudTrail with data event logging for the affected bucket will also enhance visibility into put operations, ensuring that any unauthorized access attempts are logged and can be detected by security information and event management systems. Regular audits of IAM policies using tools like AWS Access Analyzer should be conducted to identify and rectify overly permissive roles before they can be exploited in conjunction with other vulnerabilities.