CVE-2024-27019 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: Fix potential data-race in __nft_obj_type_get()
nft_unregister_obj() can concurrent with __nft_obj_type_get(), and there is not any protection when iterate over nf_tables_objects list in __nft_obj_type_get(). Therefore, there is potential data-race of nf_tables_objects list entry.
Use list_for_each_entry_rcu() to iterate over nf_tables_objects list in __nft_obj_type_get(), and use rcu_read_lock() in the caller nft_obj_type_get() to protect the entire type query process.
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Analysis
by VulDB Data Team • 02/07/2026
The vulnerability identified as CVE-2024-27019 represents a critical data-race condition within the Linux kernel's netfilter subsystem, specifically affecting the nf_tables framework. This flaw exists in the interaction between the nft_unregister_obj() function and the __nft_obj_type_get() function, creating a scenario where concurrent operations can lead to unpredictable behavior and potential system instability. The vulnerability manifests when these two functions execute simultaneously, with nft_unregister_obj() attempting to remove objects from the nf_tables_objects list while __nft_obj_type_get() is iterating through the same list to retrieve object type information. This concurrent access pattern creates a classic race condition where memory corruption or data inconsistency can occur during the list traversal operation.
The technical implementation of this vulnerability stems from inadequate synchronization mechanisms within the nf_tables_objects list management. The __nft_obj_type_get() function performs iteration over the nf_tables_objects list without proper locking mechanisms, specifically failing to use the RCU (Read-Copy-Update) infrastructure that is fundamental to safe concurrent list traversal in kernel space. This omission allows the list to be modified by nft_unregister_obj() during the iteration process, potentially causing the iterator to access freed memory locations or skip entries entirely. The absence of proper RCU protection means that the list structure can be in an inconsistent state during the read operation, leading to potential kernel panics, memory corruption, or privilege escalation opportunities. This flaw directly relates to CWE-362, which describes Race Conditions in the Common Weakness Enumeration catalog, and specifically manifests as a data race condition in kernel-level concurrent programming.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable sophisticated attack vectors within kernel space. An attacker who can trigger concurrent calls to both nft_unregister_obj() and __nft_obj_type_get() could exploit this race condition to cause system crashes, leading to denial of service conditions that could persist until system reboot. More critically, the memory corruption resulting from improper list traversal could potentially be leveraged to escalate privileges or execute arbitrary code within kernel context, representing a severe security risk. The vulnerability affects systems running Linux kernel versions where the nf_tables subsystem is actively used, particularly those implementing network filtering rules or object management functionality. The timing and conditions required to exploit this vulnerability may be somewhat complex, but the potential consequences make it a significant concern for system administrators and security professionals managing Linux-based infrastructure.
The mitigation strategy for CVE-2024-27019 involves implementing proper RCU synchronization mechanisms throughout the affected code paths. The fix requires replacing the standard list iteration with list_for_each_entry_rcu() to ensure safe concurrent access patterns, while also adding rcu_read_lock() protection in the calling function nft_obj_type_get(). This approach aligns with established kernel development practices and follows the ATT&CK framework's concept of privilege escalation through kernel vulnerabilities. System administrators should prioritize applying the kernel patches that implement these RCU protections, as they address the fundamental synchronization issue without requiring architectural changes to the netfilter subsystem. Organizations should also consider monitoring for unusual patterns in netfilter operations that might indicate exploitation attempts, while maintaining awareness of the broader implications of kernel-level race conditions in network security infrastructure. The fix demonstrates proper adherence to kernel security principles by ensuring that concurrent access patterns are properly protected through established synchronization mechanisms rather than attempting to redesign core subsystem functionality.