CVE-2025-27940: TDX Module Information Disclosure Flaw

CVE-2025-27940 Overview

CVE-2025-27940 is an out-of-bounds read vulnerability affecting Intel Trust Domain Extensions (TDX) Module versions prior to tdx1.5. This vulnerability exists within Ring 0 (Hypervisor level) and can potentially allow information disclosure through a software side-channel attack. The flaw requires a privileged attacker with local access and presents a high-complexity attack scenario that could lead to unauthorized data exposure.

Critical Impact

Privileged attackers with local access may exploit this out-of-bounds read vulnerability to disclose sensitive information from protected memory regions within Intel TDX environments, potentially compromising the confidentiality of trusted execution workloads.

Affected Products

• Intel TDX Module versions before tdx1.5
• Systems utilizing Intel Trust Domain Extensions with vulnerable TDX Module firmware

Discovery Timeline

• 2026-02-10 - CVE-2025-27940 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2025-27940

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-bounds Read), a memory corruption flaw that occurs when software reads data from a location that is outside the intended buffer boundaries. In the context of Intel TDX Module, this vulnerability exists at the hypervisor level (Ring 0), which is a particularly sensitive execution context responsible for managing trusted execution environments.

The attack leverages a software side-channel technique, requiring the attacker to have privileged access to the local system. The high attack complexity indicates that specific conditions must be present for successful exploitation, including particular system configurations or timing requirements. No user interaction is required once the attacker has established privileged local access.

The confidentiality impact is high, meaning successful exploitation could result in significant disclosure of sensitive information. However, the vulnerability does not affect system integrity or availability, and there are no subsequent impacts to other system components.

Root Cause

The root cause of this vulnerability lies in improper bounds checking within the Intel TDX Module's memory access routines. When processing certain operations at the hypervisor level, the TDX Module fails to properly validate memory boundaries before reading data, allowing an attacker to potentially read memory contents beyond the intended buffer. This out-of-bounds read condition can be exploited through a side-channel attack to extract sensitive information from protected memory regions.

Attack Vector

The attack vector is local, requiring the adversary to have privileged access to the vulnerable system. The exploitation path involves:

1. Privileged Local Access: The attacker must first obtain privileged (Ring 0 or equivalent) access to a system running the vulnerable TDX Module
2. Side-Channel Setup: The attacker establishes a software-based side-channel mechanism to observe memory access patterns
3. Triggering the Vulnerability: Specific operations are performed that cause the TDX Module to read beyond buffer boundaries
4. Information Extraction: Through careful analysis of side-channel observations, the attacker extracts confidential data from the out-of-bounds memory read

The vulnerability requires no special internal knowledge of the system and does not require user interaction. However, specific attack preconditions must be present, contributing to the overall attack complexity. For detailed technical information, refer to the Intel Security Advisory SA-01397.

Detection Methods for CVE-2025-27940

Indicators of Compromise

• Unusual memory access patterns at the hypervisor level that may indicate side-channel probing activities
• Anomalous privileged operations targeting TDX Module components
• Unexpected system behavior in Trust Domain workloads that could indicate information leakage

Detection Strategies

• Monitor for unusual privileged access attempts to TDX Module components and related hypervisor interfaces
• Implement hardware performance counter monitoring to detect potential side-channel attack patterns
• Deploy endpoint detection solutions capable of identifying anomalous Ring 0 activities

Monitoring Recommendations

• Enable comprehensive logging for hypervisor-level operations on systems running Intel TDX
• Utilize SentinelOne Singularity Platform for real-time behavioral analysis of privileged system activities
• Regularly audit privileged account access and activities on systems with TDX capabilities

How to Mitigate CVE-2025-27940

Immediate Actions Required

• Update Intel TDX Module to version tdx1.5 or later on all affected systems
• Review and restrict privileged access to systems running Intel TDX workloads
• Conduct an inventory of all systems utilizing Intel TDX to identify vulnerable deployments

Patch Information

Intel has released TDX Module version tdx1.5 which addresses this vulnerability. Organizations should apply this update following Intel's guidance provided in Intel Security Advisory SA-01397. The update should be applied through firmware update procedures appropriate for your system's hardware configuration.

Workarounds

• Implement strict access controls to limit privileged local access to systems running vulnerable TDX Module versions
• Consider isolating critical TDX workloads until the firmware update can be applied
• Monitor systems for signs of exploitation while awaiting patch deployment