CVE-2023-54119 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
inotify: Avoid reporting event with invalid wd
When inotify_freeing_mark() races with inotify_handle_inode_event() it can happen that inotify_handle_inode_event() sees that i_mark->wd got already reset to -1 and reports this value to userspace which can confuse the inotify listener. Avoid the problem by validating that wd is sensible (and pretend the mark got removed before the event got generated otherwise).
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Analysis
by VulDB Data Team • 01/03/2026
The vulnerability described in CVE-2023-54119 resides within the Linux kernel's inotify subsystem, which provides file system event monitoring capabilities to user-space applications. This subsystem enables processes to receive notifications when specific file system operations occur, making it a critical component for various monitoring and automation tools. The flaw manifests as a race condition between two key kernel functions that manage inotify watch descriptors and event handling. When the inotify_freeing_mark() function attempts to clean up a watch descriptor while inotify_handle_inode_event() is processing an event, a timing issue can occur that leads to invalid data being reported to user-space applications.
The technical root cause of this vulnerability stems from a race condition scenario where the inotify subsystem fails to properly validate watch descriptor states during concurrent operations. Specifically, when inotify_freeing_mark() executes and resets the watch descriptor identifier i_mark->wd to -1, it can occur concurrently with inotify_handle_inode_event() which is still processing a file system event. This race condition results in the event handling function reading an invalid watch descriptor value of -1 and subsequently reporting this malformed data to user-space listeners. The invalid watch descriptor value can cause confusion in applications that rely on inotify for file system monitoring, potentially leading to incorrect behavior or application crashes.
The operational impact of this vulnerability extends beyond simple data corruption, as it affects the reliability and stability of applications that depend on inotify for real-time file system monitoring. User-space applications may receive invalid watch descriptor values that do not correspond to any active watches, causing them to misinterpret file system events or fail to process events correctly. This vulnerability can particularly affect system monitoring tools, backup utilities, and file synchronization applications that rely heavily on inotify's event reporting mechanism. The race condition can occur under high system load or when multiple processes are simultaneously creating and removing file system watches, making the vulnerability more likely to manifest in production environments with intensive file system activity.
Security implications of this vulnerability align with CWE-362, which addresses race conditions in concurrent programming scenarios. The issue represents a classic timing-dependent flaw where the order of operations between kernel functions creates an inconsistent state that propagates to user-space applications. From an attacker's perspective, while this vulnerability does not directly provide privilege escalation or remote code execution capabilities, it can serve as a vector for denial-of-service attacks against applications that depend on inotify functionality. The flaw can be exploited to destabilize monitoring systems or cause cascading failures in applications that rely on proper event reporting from the inotify subsystem. Mitigation strategies should focus on ensuring proper synchronization between kernel functions and validating watch descriptor states before reporting events to user-space, as implemented in the kernel fix that validates watch descriptor sensibility and handles invalid states gracefully by pretending the mark was removed before event generation.
The fix for CVE-2023-54119 addresses the core synchronization issue by implementing proper validation checks within the inotify subsystem. The kernel patch modifies the event handling logic to verify that watch descriptor values are sensible before reporting them to user-space applications. This approach prevents invalid watch descriptor values from being propagated to applications, maintaining the integrity of the inotify event reporting mechanism. The solution follows established security practices for concurrent programming by ensuring that shared kernel data structures are properly validated before being consumed by user-space processes. This vulnerability demonstrates the importance of careful synchronization in kernel subsystems and highlights how seemingly minor race conditions can have significant impacts on system stability and application reliability. The fix represents a defensive programming approach that prioritizes data integrity over potential performance optimizations that could introduce timing-related issues.