CVE-2026-68268 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/xe: Return error on non-migratable faults requiring devmem
Non-migratable faults that require devmem incorrectly jump to the 'out' label, which squashes the error code intended to be returned to the upper layers. Fix this by returning -EACCES instead.
(cherry picked from commit c4508edb2c723de93717272488ea65b165637eac)
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Analysis
by VulDB Data Team • 08/10/2026
This vulnerability exists within the Linux kernel's graphics subsystem, specifically in the x86 graphics execution driver component that handles direct memory access operations. The flaw manifests when processing non-migratable memory faults that require direct memory access operations, creating a critical error handling path that fails to properly propagate error codes to calling layers. The issue stems from incorrect control flow logic where fault handling code transitions to an 'out' label without preserving the intended error code, effectively masking the true nature of the memory access violation.
The technical implementation involves the drm/xe driver's memory management subsystem where it processes page faults during graphics command execution. When a non-migratable fault occurs that requires direct memory access operations, the kernel's error handling mechanism incorrectly routes these conditions through an error path that returns generic success codes rather than specific error indicators. This represents a violation of proper error propagation principles and demonstrates inadequate exception handling within the graphics driver's memory management layer. The vulnerability directly impacts the kernel's ability to accurately report memory access violations and maintains an inconsistent error state throughout the call stack.
The operational impact of this vulnerability extends beyond simple error reporting failure, as it creates potential security implications for systems relying on proper memory access validation during graphics processing operations. When the driver fails to return appropriate error codes such as -EACCES for access denied conditions, it can mask legitimate security violations or memory protection faults that should be propagated to higher-level system components. This behavior could enable attackers to bypass certain memory access controls or create confusion in system monitoring and logging mechanisms that depend on accurate error reporting from kernel drivers.
The fix implemented addresses this issue by explicitly returning -EACCES error code instead of allowing the faulty control flow to squish the intended error value. This modification aligns with established kernel security practices and ensures proper error propagation through the graphics subsystem's call chain. The solution follows standard kernel development patterns for memory management error handling and maintains consistency with other similar error conditions within the same driver component. This change specifically addresses a weakness in the driver's fault handling logic that could potentially be exploited to bypass memory access controls or create false positive scenarios in system monitoring.
This vulnerability type corresponds to CWE-704 in the Common Weakness Enumeration catalog, which covers incorrect error code propagation and improper exception handling in kernel drivers. The issue demonstrates characteristics consistent with ATT&CK technique T1547.001 related to privilege escalation through kernel vulnerabilities, as improper error handling can create opportunities for attackers to manipulate system behavior. The fix represents a defensive coding practice that ensures proper error state management and maintains the integrity of system call return values throughout the graphics execution pipeline. This particular vulnerability highlights the importance of maintaining consistent error reporting mechanisms in kernel space drivers where incorrect error propagation can undermine system security and reliability.