CVE-2022-49574 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
tcp: Fix data-races around sysctl_tcp_recovery.
While reading sysctl_tcp_recovery, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.
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Analysis
by VulDB Data Team • 07/11/2025
The vulnerability identified as CVE-2022-49574 resides within the Linux kernel's implementation of the Transmission Control Protocol subsystem, specifically concerning the sysctl_tcp_recovery parameter. This issue represents a classic race condition scenario that can lead to unpredictable behavior and potential system instability. The vulnerability affects the kernel's handling of concurrent access to TCP recovery settings, where multiple threads or processes may attempt to read and modify the sysctl_tcp_recovery value simultaneously. Such concurrent operations without proper synchronization mechanisms create opportunities for data corruption and inconsistent system states.
The technical flaw manifests in the absence of proper memory barrier handling when accessing the sysctl_tcp_recovery parameter during concurrent read operations. When multiple kernel threads attempt to read this parameter while another thread modifies it, the system may observe partial or inconsistent values due to the lack of atomic access semantics. The fix implemented addresses this by introducing READ_ONCE() macro calls to ensure that readers obtain consistent values regardless of concurrent modifications. This approach aligns with established kernel development practices for handling concurrent data access patterns and prevents the propagation of stale or corrupted data values during critical TCP operations. The vulnerability falls under the category of data race conditions as defined by CWE-362, which specifically addresses concurrent execution issues where operations are not properly synchronized.
The operational impact of this vulnerability extends beyond simple data inconsistency, potentially affecting network reliability and system stability. When TCP recovery mechanisms are accessed concurrently without proper safeguards, network applications may experience unexpected behavior during connection recovery phases, leading to connection drops, performance degradation, or even system crashes in extreme cases. The vulnerability particularly impacts systems handling high volumes of concurrent TCP connections where the likelihood of race conditions increases significantly. This type of vulnerability can be exploited by malicious actors to cause denial of service conditions or to manipulate network behavior in ways that compromise system integrity. The ATT&CK framework categorizes this as a system modification technique that could be leveraged to create persistent network instability or to facilitate more sophisticated attacks by compromising the underlying network stack reliability.
Mitigation strategies for CVE-2022-49574 involve ensuring that all kernel versions containing the fix are deployed across affected systems, with particular attention to enterprise environments running critical network services. System administrators should prioritize patching operations, especially in high-availability environments where TCP reliability is paramount. The fix itself represents a defensive programming approach that can be validated through kernel testing procedures and regression testing to ensure no unintended side effects occur. Organizations should also implement monitoring solutions to detect unusual network behavior patterns that might indicate race condition exploitation attempts. Regular kernel updates and vulnerability assessments remain essential practices for maintaining network security posture, as this vulnerability demonstrates the ongoing need for careful concurrent access management in kernel space operations. The resolution of this issue reinforces the importance of proper synchronization mechanisms in kernel development and highlights the critical nature of thorough testing for concurrent access scenarios in operating system components.