CVE-2026-72027 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
mm/compaction: handle free_pages_prepare() properly in compaction_free()
free_pages_prepare() can fail but compaction_free() does not handle the failure case. Failed pages should not be added back to cc->freepages for future use, since they can be either PageHWPoison or free_page_is_bad() and might cause data corruption.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel's memory management subsystem represents a critical flaw in the compaction mechanism that could lead to data corruption and system instability. This issue resides within the mm/compaction module where the free_pages_prepare() function is called during the compaction_free() process, yet proper error handling has been omitted from the subsequent operations.
The technical root cause stems from insufficient validation of the free_pages_prepare() return value within the compaction_free() function. When this preparatory function encounters problematic pages that cannot be properly prepared for reuse, it returns an error code indicating failure. However, the compaction_free() implementation fails to check this return status and proceeds to add the potentially compromised pages back into the cc->freepages collection for future allocation cycles.
This oversight creates a dangerous scenario where pages that have been marked as PageHWPoison or determined to be bad through free_page_is_bad() checks are reintroduced into the free page pool. The implications extend beyond simple memory management inefficiencies as these corrupted pages can subsequently be allocated to processes, leading to data corruption, system crashes, or potentially exploitable conditions. The vulnerability directly relates to CWE-704, which encompasses improper handling of error conditions in memory management operations, and aligns with ATT&CK technique T1070.004 for Indicator Removal on Host related to memory manipulation.
The operational impact of this vulnerability manifests in several ways including potential system crashes during memory allocation, silent data corruption in applications that receive pages from the compromised free pool, and increased system instability under memory pressure conditions. Systems utilizing memory compaction features, particularly those with high memory churn or running memory-intensive workloads, face elevated risk exposure. The vulnerability affects the kernel's ability to maintain memory integrity and could potentially be leveraged by attackers to create persistent corruption conditions or escalate privileges through memory manipulation attacks.
Mitigation strategies should focus on implementing proper error handling within the compaction_free() function to ensure that failed pages are properly identified and excluded from future allocation cycles. The fix requires adding explicit checks for free_pages_prepare() return values and appropriate handling of failure conditions by either discarding the problematic pages or marking them as unusable. Additionally, system administrators should monitor memory health indicators and consider implementing memory testing procedures to detect hardware issues that might contribute to page corruption. Kernel updates addressing this specific vulnerability should be prioritized in production environments, particularly those running memory-intensive applications where compaction is actively utilized.