Summaryinfo

A vulnerability categorized as problematic has been discovered in ultravioletrs cocos up to 0.8.1. This impacts an unknown function of the component CoCoS Service. The manipulation results in key exchange without entity authentication. This vulnerability is reported as CVE-2026-33697. The attack requires a local approach. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in ultravioletrs cocos up to 0.8.1. Affected is an unknown functionality of the component CoCoS Service. The manipulation with an unknown input leads to a key exchange without entity authentication vulnerability. CWE is classifying the issue as CWE-322. The product performs a key exchange with an actor without verifying the identity of that actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Cocos AI is a confidential computing system for AI. The current implementation of attested TLS (aTLS) in CoCoS is vulnerable to a relay attack affecting all versions from v0.4.0 through v0.8.2. This vulnerability is present in both the AMD SEV-SNP and Intel TDX deployment targets supported by CoCoS. In the affected design, an attacker may be able to extract the ephemeral TLS private key used during the intra-handshake attestation. Because the attestation evidence is bound to the ephemeral key but not to the TLS channel, possession of that key is sufficient to relay or divert the attested TLS session. A client will accept the connection under false assumptions about the endpoint it is communicating with — the attestation report cannot distinguish the genuine attested service from the attacker's relay. This undermines the intended authentication guarantees of attested TLS. A successful attack may allow an attacker to impersonate an attested CoCoS service and access data or operations that the client intended to send only to the genuine attested endpoint. Exploitation requires the attacker to first extract the ephemeral TLS private key, which is possible through physical access to the server hardware, transient execution attacks, or side-channel attacks. Note that the aTLS implementation was fully redesigned in v0.7.0, but the redesign does not address this vulnerability. The relay attack weakness is architectural and affects all releases in the v0.4.0–v0.8.2 range. This vulnerability class was formally analyzed and demonstrated across multiple attested TLS implementations, including CoCoS, by researchers whose findings were disclosed to the IETF TLS Working Group. Formal verification was conducted using ProVerif. As of time of publication, there is no patch available. No complete workaround is available. The following hardening measures reduce but do not eliminate the risk: Keep TEE firmware and microcode up to date to reduce the key-extraction surface; define strict attestation policies that validate all available report fields, including firmware versions, TCB levels, and platform configuration registers; and/or enable mutual aTLS with CA-signed certificates where deployment architecture permits.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-33697 since 03/23/2026. The exploitability is told to be difficult. Local access is required to approach this attack. The technical details are unknown and an exploit is not available.

Upgrading to version 0.8.2 eliminates this vulnerability.

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Productinfo

Vendor

• ultravioletrs

Name

• cocos

Version

• 0.8.0
• 0.8.1

Website

• Product: https://github.com/ultravioletrs/cocos/

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