CVE-2022-50293 in Linux
Summary
by MITRE • 09/15/2025
In the Linux kernel, the following vulnerability has been resolved:
btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range
If we get -ENOMEM while dropping file extent items in a given range, at btrfs_drop_extents(), due to failure to allocate memory when attempting to increment the reference count for an extent or drop the reference count, we handle it with a BUG_ON(). This is excessive, instead we can simply abort the transaction and return the error to the caller. In fact most callers of btrfs_drop_extents(), directly or indirectly, already abort the transaction if btrfs_drop_extents() returns any error.
Also, we already have error paths at btrfs_drop_extents() that may return -ENOMEM and in those cases we abort the transaction, like for example anything that changes the b+tree may return -ENOMEM due to a failure to allocate a new extent buffer when COWing an existing extent buffer, such as a call to btrfs_duplicate_item() for example.
So replace the BUG_ON() calls with proper logic to abort the transaction and return the error.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/10/2026
The vulnerability identified as CVE-2022-50293 resides within the Linux kernel's btrfs file system implementation, specifically in the btrfs_drop_extents() function. This flaw represents a critical issue in error handling that could potentially lead to system instability or denial of service conditions. The vulnerability manifests when the btrfs file system encounters memory allocation failures during the process of dropping file extent items within a specified range, particularly when attempting to increment or decrement reference counts for extents. The improper handling of these memory allocation failures through the use of BUG_ON() macros instead of graceful error recovery mechanisms creates a pathway for system crashes or unexpected behavior.
The technical root cause of this vulnerability stems from the kernel's btrfs implementation treating memory allocation failures as unrecoverable system errors rather than manageable conditions. When btrfs_drop_extents() encounters -ENOMEM errors during extent item operations, the current implementation uses BUG_ON() macros which immediately terminate the kernel execution, bypassing normal error handling procedures. This approach is fundamentally flawed because memory allocation failures, while serious, are not necessarily catastrophic system errors that warrant immediate kernel panic. The function operates within the context of transaction management where proper error propagation and transaction abortion should occur instead of abrupt system termination.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise the stability and reliability of systems utilizing btrfs file systems. When memory allocation fails during extent management operations, the system could experience unexpected kernel panics that result in complete system shutdowns or reboot cycles. This is particularly concerning in production environments where continuous availability is critical, as such failures could lead to data loss or service disruption. The vulnerability affects systems running Linux kernels with btrfs file systems, making it relevant to a broad range of enterprise and server deployments that rely on this advanced file system implementation.
The fix implemented for CVE-2022-50293 addresses the core issue by replacing the BUG_ON() calls with proper transaction management and error propagation mechanisms. This remediation aligns with established kernel development practices and security standards, ensuring that memory allocation failures are handled gracefully within the existing transaction framework. The solution follows the principle that -ENOMEM errors should trigger transaction abortion and proper error return to callers rather than system termination. This approach is consistent with the broader ATT&CK framework's consideration of kernel-level vulnerabilities and aligns with CWE-704, which addresses improper handling of exceptional conditions in kernel code. The fix ensures that existing error handling paths within btrfs_drop_extents() are properly leveraged, maintaining consistency with the file system's established transaction management protocols and preventing the escalation of memory allocation failures into system-wide failures.
The mitigation strategy for this vulnerability involves updating affected Linux systems to kernel versions containing the patched btrfs implementation. System administrators should prioritize applying these updates, particularly in production environments where btrfs file systems are actively used. Monitoring for system stability and kernel log analysis should be conducted to identify any potential issues related to memory allocation during file system operations. Organizations utilizing btrfs should also consider implementing additional memory management monitoring and alerting mechanisms to detect potential resource exhaustion conditions that could lead to similar vulnerabilities. The fix demonstrates the importance of proper error handling in kernel space and reinforces the principle that resource allocation failures should be managed through established transactional mechanisms rather than abrupt system termination. This vulnerability highlights the critical need for robust error handling in file system implementations and underscores the importance of following established security practices in kernel development.