VU#431093: TCG TPM 2.0 reference code found vulnerable to information leakage and timing side-channel attacks

Overview

Two vulnerabilities have been identified in the Trusted Platform Module (TPM) 2.0 reference implementation:

1. CVE-2026-6726 – Information leakage via falsified TPM keys.
2. CVE-2026-6727 – A timing side-channel vulnerability in RSA OAEP decryption.

An attacker with privileged access to a TPM command interface may be able to exploit these vulnerabilities by sending specially crafted TPM commands. Successful exploitation could allow the attacker to decrypt ciphertexts encrypted to affected TPM-managed RSA keys, including the RSA Endorsement Key (EK), or obtain credentials for falsified TPM keys, enabling forged TPM 2.0 attestations.
These vulnerabilities are also documented by the Trusted Computing Group (TCG) in advisories - TCGVRT010 and TCGVRT0011:

Description

Trusted Platform Module (TPM) technology provides hardware-backed cryptographic services for modern computing platforms. TPMs are designed to resist tampering and may be implemented as discrete chips, integrated hardware, firmware-based TPMs (fTPMs), or software implementations used in cloud and virtualized environments.
The Trusted Computing Group (TCG) maintains the TPM specifications and publishes a reference implementation to assist vendors in developing TPM-compliant products.

Two vulnerabilities were identified in the TPM 2.0 reference implementation.

CVE-2026-6727
A timing side-channel vulnerability exists in the RSA OAEP decryption implementation. A privileged local attacker with access to the TPM command interface may be able to exploit timing differences to recover information that could allow decryption of ciphertexts encrypted to TPM-managed RSA keys, including the RSA Endorsement Key (EK), including import blobs, credential blobs, and session salts. Under certain conditions, this may also enable the forgery of TPM 2.0 attestations.