CVE-2026-92702 in Cocos
Summary
by MITRE • 09/18/2026
Cocos AI is a confidential computing system for running AI workloads inside trusted execution environments. In versions up to and including 0.8.2, the intra-handshake attested TLS (aTLS) AMD SEV-SNP verification path does not enforce attestation freshness when the expected reportData value is nil, empty, or omitted, leaving the SEV-SNP policy ReportData unset so the verifier accepts unrelated or stale Evidence not bound to the current connection. A relying party that uses this path without an expected reportData as a trust or authorization decision can be induced to trust an unintended attestation context; a supplied non-empty reportData is still validated. The issue is fixed in version 0.9.0.
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Analysis
by VulDB Data Team • 09/18/2026
Cocos AI operates as a confidential computing platform designed to execute artificial intelligence workloads within secure Trusted Execution Environments, leveraging hardware-level isolation provided by AMD Secure Encrypted Virtualization with Secure Nested Paging technology. This architecture relies heavily on remote attestation protocols to establish trust between the client and the server before any sensitive data is exchanged or processed. The intra-handshake attested TLS mechanism serves as a critical security control within this ecosystem, ensuring that both parties verify each other's integrity and identity during the initial connection phase. By embedding attestation evidence directly into the Transport Layer Security handshake, Cocos AI aims to prevent man-in-the-middle attacks and ensure that computations are performed only on verified, untampered hardware configurations.
A significant vulnerability was identified in versions of Cocos AI up through 0.8.2 concerning the verification logic for AMD SEV-SNP reports during this attestation process. Specifically, when the expected reportData field is nil, empty, or omitted by the relying party, the system fails to enforce freshness checks on the incoming attestation evidence. In a properly secured implementation, the verifier should bind the current connection session to specific data within the hardware-generated report, typically via the reportData field which can be populated with random nonces or context-specific identifiers. Without this binding mechanism and without verifying that the evidence is fresh relative to the current handshake, an attacker could potentially replay old attestation evidence from a different context or even unrelated sessions. This flaw effectively decouples the identity verification from the specific connection being established, allowing stale or misappropriated credentials to be accepted as valid for the current session.
The operational impact of this vulnerability is severe because it undermines the core promise of confidential computing: that code and data are protected not only by encryption but also by strict access controls based on verified hardware state. If a relying party utilizes this specific path without providing an expected reportData value, they may be induced to trust an attestation context that does not correspond to their intended security policy or authorization requirements. This could lead to unauthorized access to sensitive AI models or training data if the system accepts evidence from a compromised or unintended environment. It is important to note that this flaw only affects scenarios where no non-empty reportData is supplied; when such data is provided, the validation logic correctly verifies its presence and integrity, thereby maintaining security for those specific configurations.
This issue aligns with CWE-345, which describes Insufficient Verification of Data Authenticity, as well as CWE-296, Improper Supplementation of Authentication Mechanisms, since the system fails to adequately supplement the basic TLS handshake with robust binding to session-specific context. From an adversarial perspective, this vulnerability facilitates ATT&CK technique T1078, Valid Accounts, by allowing attackers to reuse previously valid credentials or attestation evidence in unauthorized contexts. It also relates to MITMATTACK vectors where stale tokens are replayed to bypass authentication checks. The lack of freshness verification means that even if the underlying hardware is secure at the time of original attestation, reusing that proof later does not guarantee current security posture, especially if the system state has changed or been compromised since then.
To mitigate this risk, organizations running Cocos AI must upgrade to version 0.9.0 or later, where the verification path has been corrected to enforce strict freshness checks regardless of whether reportData is explicitly provided by the relying party. For environments that cannot immediately patch, administrators should ensure that all client configurations strictly provide a non-empty expected reportData value during attestation requests. This forces the server to validate against specific session-bound data, thereby preventing the acceptance of stale or unrelated evidence. Regular audits of configuration files and dependency updates are essential to maintain the integrity of confidential computing pipelines, ensuring that hardware-enforced security boundaries remain effective against evolving threats targeting remote attestation mechanisms.