CVE-2026-68324 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
iommu/intel: Fix out-of-bounds memset in dmar_latency_disable()
dmar_latency_disable() intends to zero out only the single latency_statistic entry for the given type, but the memset size was computed as sizeof(*lstat) * DMAR_LATENCY_NUM, which clears the entire array starting from &lstat[type].
When type > 0, this writes beyond the end of the allocated array, corrupting adjacent memory.
Fix by using sizeof(*lstat) to clear only the target entry.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability identified in the Linux kernel's Intel IOMMU subsystem represents a critical out-of-bounds memory access flaw that could lead to system instability and potential security implications. This issue resides within the dmar_latency_disable() function which handles latency statistics for DMA remapping operations. The problem specifically manifests when processing latency statistic entries for different types of DMA operations, where improper memory management creates a buffer overflow condition that extends beyond intended array boundaries.
The technical implementation flaw stems from incorrect memory manipulation within the kernel's device memory access controller driver. The function computes the memory copy size using sizeof(lstat) DMAR_LATENCY_NUM rather than the appropriate single entry size of sizeof(*lstat). This miscalculation causes the memset operation to overwrite not just the targeted latency_statistic entry but also subsequent array elements in memory, creating a classic out-of-bounds write vulnerability. When the type parameter exceeds zero, this error becomes particularly dangerous as it begins writing beyond the allocated memory region starting from the specified array index.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially compromise system stability and integrity. Such out-of-bounds writes can lead to unpredictable behavior in kernel memory management, potentially causing system crashes, data corruption, or in extreme cases, privilege escalation opportunities that align with ATT&CK technique T1068 for privilege escalation through local exploitation. The vulnerability affects systems utilizing Intel IOMMU hardware where DMA operations are performed, making it particularly relevant for server environments, cloud infrastructure, and virtualization platforms that rely heavily on memory management controls.
Security researchers categorize this vulnerability under CWE-787 Out-of-bounds Write as it represents a direct violation of memory boundary constraints within kernel space operations. The fix implemented addresses the root cause by modifying the memset size parameter to use sizeof(*lstat) instead of the array multiplication, ensuring that only the specific target entry gets cleared without affecting adjacent memory locations. This remediation aligns with secure coding practices recommended in industry standards and directly prevents the memory corruption that could otherwise be exploited by malicious actors. The solution follows established mitigation patterns for buffer overflow vulnerabilities while maintaining the intended functionality of the latency statistic management system.
Systems administrators should prioritize patching this vulnerability across all Linux kernel versions containing the affected Intel IOMMU driver code, particularly in environments where DMA operations are frequent or critical to system operation. The fix demonstrates proper memory management practices that prevent unintended memory access patterns and reinforces the importance of careful boundary calculations in kernel-level programming. This vulnerability serves as an example of how seemingly minor coding errors in memory management can have significant security implications, emphasizing the need for thorough code review processes and automated testing for buffer overflow conditions in operating system kernel components.