CVE-2026-23317 in Linux
Summary
by MITRE • 03/25/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/vmwgfx: Return the correct value in vmw_translate_ptr functions
Before the referenced fixes these functions used a lookup function that returned a pointer. This was changed to another lookup function that returned an error code with the pointer becoming an out parameter.
The error path when the lookup failed was not changed to reflect this change and the code continued to return the PTR_ERR of the now uninitialized pointer. This could cause the vmw_translate_ptr functions to return success when they actually failed causing further uninitialized and OOB accesses.
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Analysis
by VulDB Data Team • 05/04/2026
The vulnerability identified as CVE-2026-23317 resides within the Linux kernel's VMware graphics driver component, specifically affecting the drm/vmwgfx subsystem. This issue represents a critical flaw in error handling mechanisms that can lead to severe security implications. The vulnerability manifests in the vmw_translate_ptr functions which are responsible for translating virtual memory addresses within the graphics driver context. These functions serve as essential components in the kernel's graphics subsystem, particularly when managing memory operations for virtualized graphics environments.
The technical flaw stems from a code refactoring that altered the behavior of underlying lookup functions within the driver. Originally, the lookup function would return a direct pointer value, but the implementation was modified to return an error code while making the pointer an out parameter instead. This change in function signature and behavior was not consistently applied throughout the error handling pathways. The error path implementation failed to account for this transition, resulting in the code continuing to return PTR_ERR values from an uninitialized pointer variable. This fundamental mismatch between expected and actual function behavior creates a dangerous condition where error states are incorrectly interpreted as successful operations.
The operational impact of this vulnerability extends beyond simple functional failure into potential security exploitation scenarios. When the vmw_translate_ptr functions encounter lookup failures, they incorrectly return success codes instead of proper error indicators. This misbehavior leads to subsequent code paths that operate on uninitialized memory or perform out-of-bounds memory accesses. The consequences can include arbitrary code execution, privilege escalation, or system instability within virtualized graphics environments. Attackers could potentially leverage this vulnerability to bypass security controls or gain unauthorized access to system resources through carefully crafted graphics operations that trigger the flawed error handling path.
This vulnerability aligns with CWE-252, which describes "Unchecked Return Value" conditions where the return value of a function is not properly checked or handled, and also relates to CWE-476, "NULL Pointer Dereference" since the uninitialized pointer issue can lead to dereferencing invalid memory addresses. From an ATT&CK perspective, this vulnerability could be categorized under T1068, "Exploitation for Privilege Escalation" and potentially T1211, "Exploitation for Defense Evasion" when exploited within virtualized environments. The flaw demonstrates poor software engineering practices in maintaining consistent error handling across function interfaces, particularly in kernel space where such issues can have far-reaching consequences for system integrity and security. The vulnerability underscores the critical importance of thorough testing and validation when refactoring code, especially in security-sensitive kernel components where error handling correctness is paramount for system stability and protection against exploitation.
Mitigation strategies should focus on implementing comprehensive testing procedures for all code paths, particularly those involving error handling and memory management. System administrators should ensure timely application of security patches and updates from kernel vendors. Additionally, monitoring for unusual memory access patterns or system instability in virtualized environments using VMware graphics drivers can help detect potential exploitation attempts. The vulnerability highlights the necessity of rigorous code review processes and automated testing frameworks that can catch such inconsistencies in function behavior and error handling implementations.