CVE-2025-39710 in Linux
Summary
by MITRE • 09/05/2025
In the Linux kernel, the following vulnerability has been resolved:
media: venus: Add a check for packet size after reading from shared memory
Add a check to ensure that the packet size does not exceed the number of available words after reading the packet header from shared memory. This ensures that the size provided by the firmware is safe to process and prevent potential out-of-bounds memory access.
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Analysis
by VulDB Data Team • 02/09/2026
The vulnerability identified as CVE-2025-39710 resides within the Linux kernel's venus media driver, which is responsible for handling video decoding operations on Qualcomm Snapdragon platforms. This driver operates in a unique environment where firmware components communicate with the kernel through shared memory regions, creating a complex interaction that requires careful validation of data integrity. The venus driver manages hardware acceleration for video processing tasks, making it a critical component in mobile and embedded systems where performance and security are paramount. The shared memory communication model introduces inherent risks when firmware provides metadata that dictates memory access patterns, as this data can potentially be manipulated or contain erroneous values.
The technical flaw manifests as a missing validation check in the packet processing logic of the venus driver. When firmware sends packet headers through shared memory, the driver reads these headers to determine packet size and subsequently allocates or processes memory regions accordingly. The vulnerability occurs because the driver does not verify that the packet size specified in the firmware header falls within acceptable bounds relative to the available memory space in the shared region. This oversight creates a potential out-of-bounds memory access condition where the driver might attempt to read beyond the allocated shared memory boundaries, leading to memory corruption and potential privilege escalation.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a classic buffer over-read scenario that can be exploited to gain unauthorized access to system resources. Attackers could potentially craft malicious firmware packets that specify oversized packet sizes, causing the venus driver to access memory locations outside the intended shared memory region. This condition could lead to system instability, denial of service, or more severe consequences depending on the execution context and privilege levels involved. The vulnerability is particularly concerning in mobile environments where the venus driver handles sensitive video processing operations for multimedia applications and system services.
Mitigation strategies for CVE-2025-39710 should focus on implementing robust input validation mechanisms within the venus driver's packet processing pipeline. The fix involves adding a boundary check that verifies the packet size read from firmware headers against the available memory space in the shared region, ensuring that no out-of-bounds access can occur. This approach aligns with the principle of least privilege and defensive programming practices recommended in cybersecurity frameworks. The solution should be integrated at the point where firmware packet headers are processed, validating that the size parameter does not exceed the remaining capacity in the shared memory buffer. Additionally, system administrators should ensure timely kernel updates and maintain monitoring of video processing operations for anomalous behavior that might indicate exploitation attempts.
This vulnerability type maps directly to CWE-129, which addresses improper validation of array index or buffer size, and represents a common pattern in kernel drivers where firmware-provided metadata lacks sufficient validation. The ATT&CK framework categorizes this as a privilege escalation technique through kernel vulnerabilities, specifically targeting the kernel's memory management subsystem. The fix implemented in the venus driver demonstrates proper input validation practices that should be applied across similar kernel subsystems handling shared memory communications with firmware components, reinforcing the importance of defensive programming in kernel space operations where memory safety directly impacts system integrity.