CVE-2024-27420 in Linux
Summary
by MITRE • 05/17/2024
In the Linux kernel, the following vulnerability has been resolved:
netrom: Fix a data-race around sysctl_netrom_link_fails_count
We need to protect the reader reading the sysctl value because the value can be changed concurrently.
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Analysis
by VulDB Data Team • 05/25/2026
The vulnerability identified in the Linux kernel represents a classic data-race condition affecting the netrom subsystem's sysctl parameter sysctl_netrom_link_fails_count. This issue occurs within the network layer where concurrent access to a shared system control parameter creates potential for inconsistent or corrupted data reads. The netrom protocol implementation, which handles network routing for certain specialized network topologies, suffers from improper synchronization mechanisms when multiple processes or threads attempt to access the link fails count value simultaneously. This particular vulnerability falls under the broader category of race conditions that can lead to unpredictable system behavior and potential security implications.
The technical flaw manifests when readers attempt to access the sysctl_netrom_link_fails_count value while writers are simultaneously modifying it through system calls or configuration changes. Without proper synchronization primitives such as mutex locks or atomic operations, the kernel's netrom subsystem can return inconsistent data values or experience partial updates during concurrent access scenarios. This type of race condition represents a CWE-362 weakness, specifically categorized as a concurrent execution using shared data structure without proper synchronization. The vulnerability impacts the integrity of network configuration parameters and can potentially lead to incorrect routing decisions based on stale or corrupted link failure counts.
The operational impact of this vulnerability extends beyond simple data inconsistency issues as it can affect network reliability and stability within systems utilizing the netrom protocol. When multiple processes attempt to monitor or modify network link failure statistics simultaneously, the system may exhibit unpredictable behavior in routing decisions, potentially leading to network partitions or incorrect path selections. The vulnerability could be exploited by malicious actors to manipulate network routing behavior through careful timing of concurrent access patterns, though the direct security implications are primarily related to data corruption rather than privilege escalation. This issue particularly affects systems running specialized network configurations where netrom protocol support is enabled and actively used.
Mitigation strategies for this vulnerability require implementing proper synchronization mechanisms around the sysctl_netrom_link_fails_count parameter access. The recommended approach involves applying mutex locks or other atomic synchronization primitives to protect the critical section where the value is read or modified. This solution aligns with ATT&CK technique T1068 by ensuring proper resource management and prevents potential exploitation through race condition attacks. System administrators should ensure that kernel updates containing the fix are applied promptly, as the vulnerability exists in the core networking subsystem and affects all systems with netrom protocol support. The fix typically involves adding appropriate locking mechanisms around the sysctl access functions to ensure atomic operations when reading or writing the link fails count value, thereby preventing concurrent access conflicts that could lead to data corruption or inconsistent network behavior.