CVE-2025-29829
Trusted Runtime Interface Driver -- information disclosure via uninitialized resource
Summary
| Field | Value |
|---|---|
| Driver | Trusted Runtime Interface Driver |
| Vulnerability Class | Information Disclosure (Uninitialized Memory) |
| CVSS | 5.5 |
| Exploited ITW | No |
| Patch Date | April 8, 2025 |
Root Cause
The Trusted Runtime Interface Driver provides a communication channel between user-mode applications and the trusted execution environment. When user-mode code queries this interface, the driver allocates response buffers in kernel memory and returns them to the caller. The problem is that these buffers are not zeroed before being populated and returned.
Uninitialized kernel memory is not empty. It contains remnants of whatever previously occupied that memory region: kernel addresses, fragments of other processes' data, internal structure fields, or security tokens. When the driver returns an uninitialized buffer to user mode, all of that residual data leaks across the kernel/user boundary.
This is one of the most common vulnerability classes in kernel drivers, and one of the easiest to avoid (a single RtlZeroMemory call). Yet it persists because developers focus on populating the fields they intend to return and overlook the gaps between those fields, where padding, alignment bytes, or unused portions of the buffer contain stale kernel data.
Exploitation
The attacker calls the trusted runtime interface repeatedly, collecting the uninitialized data from each response. Over many iterations, the leaked data provides a statistical picture of kernel memory layout. Kernel base addresses appear frequently enough to defeat KASLR with high confidence.
The information disclosure is not directly exploitable for code execution. Its value is as a supporting primitive in a multi-stage exploit chain: the attacker uses this bug to learn kernel addresses, then applies a separate memory corruption vulnerability to achieve code execution at those known addresses.
Exploitation Primitive
Trusted runtime interface query
--> driver returns buffer with uninitialized kernel memory
--> leaked kernel addresses
--> KASLR bypass (supporting primitive for separate memory corruption exploit)
Broader Significance
Uninitialized memory bugs are the information disclosure equivalent of low-hanging fruit. They are easy to find through static analysis or fuzzing, easy to fix with a single zeroing call, and easy to exploit with a simple query loop. CVE-2025-29829 is a reminder that even trusted platform components, drivers that interface with secure execution environments, can contain basic hygiene failures. For driver developers, the lesson is to zero all output buffers unconditionally, regardless of how much useful data they contain.