CVE-2026-108266: CWE-346: Origin Validation Error in Privasys rustls

Privasys rustls, a fork of the rustls TLS library adding RA-TLS challenge and channel-binding support, had a vulnerability (CWE-346) in versions prior to 0.8.1. The RA-TLS challenge certificates generated did not bind the quote ReportData to the active TLS session, only to the certificate public key and client nonce. This flaw allowed an attacker who obtained an enclave TLS private key to relay a genuine RA-TLS quote onto a different TLS connection. As a result, a relying party could be tricked into accepting a connection terminated by an attacker as if it were from the attested enclave. The vulnerability is addressed by the fix introduced in version 0.8.1.

An attacker who obtains an enclave TLS private key can relay a valid RA-TLS quote onto a different TLS session, causing the relying party to mistakenly trust an attacker-terminated connection as originating from the attested enclave. This undermines the trust model of RA-TLS attestation and can lead to unauthorized access or man-in-the-middle scenarios. The CVSS 4.0 score is 9.1 (critical), reflecting the high impact of this vulnerability.

Upgrade to Privasys rustls version 0.8.1 or later, where this origin validation error has been fixed. No other mitigations are indicated by the vendor advisory.