Privasys Enclave OS Virtual Patched Critical TLS Relay Vulnerability

Privasys has released patches for a critical security vulnerability in its Enclave OS Virtual platform that allowed attackers to bypass attestation checks through TLS relay attacks. The flaw, tracked as CVE-2026-108268, affects versions of the software prior to tdx-v0.2.43 and tdx-gpu-v0.6.27.

The vulnerability stems from a design error in the Trusted Domain Extensions (TDX) and GPU Remote Attestation Transport Layer Security (RA-TLS) certificate issuance process. According to the National Vulnerability Database, the certificate issuer placed the public-key hash and client nonce into the quote ReportData but failed to include a value bound to the active TLS session.

This omission meant that an attacker who had obtained an enclave TLS private key could take a genuine attestation quote and relay it to a different connection. Consequently, a relying party would accept the attacker-terminated connection as if it were the legitimately attested enclave, undermining the end-to-end attestation guarantees of the confidential virtual machines.

Technical Context

Enclave OS Virtual is designed to run container workloads inside confidential virtual machines, relying on strict attestation processes to verify the integrity of the environment. The RA-TLS protocol is a critical component of this verification, ensuring that the communication channel between the enclave and the relying party is secure and authentic.

The specific weakness is classified under CWE-346, which relates to insufficient verification of data authenticity. By failing to bind the attestation data to the specific TLS session, the system created a window for replay or relay attacks. While the attacker needed to possess the enclave TLS private key to initiate the exploit, the impact was severe because it allowed them to impersonate the enclave to external parties. This breaks the trust model that confidential computing relies on, where the relying party must be certain it is communicating with the specific, verified instance of the software it expects.

The National Vulnerability Database has assigned a CVSS score of 9.1 to this issue, categorizing it as Critical. This high severity rating reflects the potential for complete compromise of the attestation process, which is foundational to the security of the enclave environment.

Affected Versions

The vulnerability impacts Privasys Enclave OS Virtual users running specific versions of the TDX and GPU components. Systems running versions prior to tdx-v0.2.43 are affected. Similarly, environments utilizing the GPU component prior to version tdx-gpu-v0.6.27 are vulnerable.

Organizations using these older versions are exposed to the risk of man-in-the-middle style attacks where the integrity of the attestation cannot be guaranteed. The fix has been confirmed in the aforementioned versions, tdx-v0.2.43 and tdx-gpu-v0.6.27. Users are advised to verify their current version numbers and upgrade to the patched releases to mitigate this risk.

What should you do?

Security teams should immediately audit their environments to determine if they are running vulnerable versions of Privasys Enclave OS Virtual. If vulnerable versions are in use, prioritize upgrading to tdx-v0.2.43 or tdx-gpu-v0.6.27. Monitor network logs for unusual TLS handshake patterns that might indicate relay attempts. Verify that attestation checks are being performed correctly by relying parties.