CVE-2026-92701: Cocos AI Intel TDX Auth Bypass Vulnerability

CVE-2026-92701 Overview

Cocos AI is a confidential computing system that runs artificial intelligence workloads inside trusted execution environments (TEEs). CVE-2026-92701 affects the intra-handshake attested TLS (aTLS) verification path used with Intel Trust Domain Extensions (TDX). The vulnerability, tracked as [CWE-346] Origin Validation Error, allows an attacker to bypass session-to-attestation binding. Cocos AI versions up to and including 0.8.2 fail to enforce that the REPORT_DATA field in a TDX QuoteV4 Evidence matches the freshness value expected for the current session.

Critical Impact
A relying party can accept structurally valid TDX Evidence with mismatched or reused reportData, releasing application data to an unintended attestation context after the handshake completes.

Affected Products

Cocos AI versions 0.1.0 through 0.8.2
Deployments using the intra-handshake aTLS Intel TDX verification path
Confidential AI workloads relying on Cocos for TEE attestation

Discovery Timeline

2026-09-18 - CVE-2026-92701 published to the National Vulnerability Database
2026-09-24 - Last updated in NVD database

Technical Details for CVE-2026-92701

Vulnerability Analysis

Cocos AI implements attested TLS to cryptographically bind a TLS session to a specific TEE instance. During the handshake, the relying party challenges the enclave with a session-specific freshness nonce. The enclave is expected to return this nonce inside the REPORT_DATA field of a signed TDX quote. The relying party then validates the quote signature and confirms that REPORT_DATA matches the expected value.

The intra-handshake TDX verification path in Cocos AI omits the second step. The code fails to copy the expected current-session freshness value into the TDX quote-body policy before invoking quote validation. As a result, any structurally valid TDX QuoteV4 Evidence passes verification regardless of whether REPORT_DATA matches the session challenge.

Root Cause

The root cause is an origin validation error [CWE-346]. The verification policy structure is passed to the TDX quote validator without being populated with the session-bound expected reportData value. The validator therefore treats the REPORT_DATA field as unconstrained. The cryptographic signature check on the quote succeeds, but the binding between the TLS session and the attestation evidence is never enforced.

Attack Vector

An attacker positioned to supply Evidence during a Cocos aTLS handshake can replay a previously issued TDX quote from an unrelated attestation context or substitute a quote generated for a different session. Because the network-reachable verification path does not require authentication or user interaction, the attacker can trigger session-misbinding remotely. Once the handshake completes, the relying party releases application data, including confidential AI model inputs or outputs, into a session that is not bound to the intended verified enclave. Full technical details are documented in the GitHub Security Advisory GHSA-4px3-wj2x-xx47.

Detection Methods for CVE-2026-92701

Indicators of Compromise

TDX QuoteV4 Evidence accepted during aTLS handshakes where the REPORT_DATA field does not match the session freshness nonce issued by the relying party.
Repeated appearances of identical TDX quotes across distinct aTLS sessions, indicating quote reuse.
aTLS sessions that complete successfully against Cocos AI versions 0.8.2 or earlier without server-side logging of REPORT_DATA comparison.

Detection Strategies

Instrument the aTLS relying party to log the expected session nonce alongside the REPORT_DATA value extracted from each received TDX quote, and alert on mismatches.
Compare deployed Cocos AI binary versions against the fixed release 0.9.0 and flag any workload running an affected version.
Correlate network telemetry to identify anomalous confidential workload sessions where the client identity or origin diverges from the attested TEE identity.

Monitoring Recommendations

Continuously monitor Cocos AI service logs for aTLS handshake completions and confidential data releases.
Track outbound data flows from confidential AI workloads to identify unexpected relying parties consuming attested sessions.
Ingest workload and TEE attestation telemetry into a centralized data lake for retrospective analysis of quote reuse patterns.

How to Mitigate CVE-2026-92701

Immediate Actions Required

Upgrade all Cocos AI deployments to version 0.9.0 or later, which enforces REPORT_DATA validation against the expected session freshness value.
Inventory all confidential AI workloads that rely on Cocos aTLS with Intel TDX and prioritize patching for internet-reachable relying parties.
Rotate any secrets, model artifacts, or session material that may have been released through a misbound aTLS session.

Patch Information

The issue is fixed in Cocos AI version 0.9.0. The patched release copies the expected current-session freshness value into the TDX quote-body policy before quote validation, ensuring that the REPORT_DATA field is compared against the session challenge. Release notes are available at GitHub Release v0.9.0.

Workarounds

If immediate upgrade is not possible, disable the intra-handshake aTLS Intel TDX verification path and require out-of-band attestation verification before releasing application data.
Restrict network exposure of Cocos AI relying parties so only trusted, authenticated clients can initiate aTLS handshakes.
Implement application-layer checks that independently verify the REPORT_DATA field of received TDX quotes against per-session nonces before trusting handshake output.

bash

# Upgrade Cocos AI to the patched release
git clone https://github.com/ultravioletrs/cocos.git
cd cocos
git checkout v0.9.0
make build