CVE-2022-49597 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_base_mss.
While reading sysctl_tcp_base_mss, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.
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Analysis
by VulDB Data Team • 06/13/2025
The vulnerability identified as CVE-2022-49597 represents a critical data race condition within the Linux kernel's TCP implementation that specifically affects the sysctl_tcp_base_mss parameter. This issue occurs in the kernel's networking subsystem where concurrent access to shared memory locations creates potential for inconsistent data retrieval and system instability. The vulnerability is classified under CWE-362, which specifically addresses race conditions in software systems where multiple threads or processes access shared resources without proper synchronization mechanisms. The problem manifests when the tcp_base_mss parameter is being read simultaneously while another process attempts to modify it, creating a scenario where readers may observe partially updated or corrupted data values.
The technical flaw stems from inadequate memory access synchronization within the kernel's TCP stack implementation. When the sysctl_tcp_base_mss parameter is accessed by multiple kernel threads or processes concurrently, there exists no proper atomic read operation to ensure data consistency. The fix implemented addresses this by incorporating READ_ONCE() macro calls in all reader contexts of this parameter, which provides a mechanism to prevent compiler optimizations from reordering memory accesses and ensures that readers observe consistent values. This approach aligns with kernel security best practices and follows the established patterns for handling concurrent access to shared kernel data structures. The vulnerability specifically impacts kernel versions where proper memory barrier implementation was missing during parameter reads, creating a window where inconsistent parameter values could be processed by TCP connection handling routines.
The operational impact of CVE-2022-49597 extends beyond simple data inconsistency issues to potentially affect network connectivity and system stability. When concurrent access to tcp_base_mss occurs during active network operations, it can lead to malformed TCP segments, connection failures, or unpredictable behavior in network stack operations. The vulnerability creates a potential attack surface where malicious actors could exploit timing variations to induce system instability or perform denial of service attacks against network services. In production environments running affected kernel versions, this race condition could result in intermittent network failures, connection resets, or degraded network performance that might be difficult to diagnose due to the intermittent nature of the race condition. The risk is particularly elevated in high-throughput network environments where multiple processes frequently access TCP configuration parameters concurrently.
Mitigation strategies for CVE-2022-49597 primarily involve upgrading to kernel versions that include the patched implementation, which properly implements READ_ONCE() semantics for the affected parameter. System administrators should prioritize applying security patches from their respective kernel vendors as soon as possible, particularly in production environments where network stability is critical. The fix represents a standard defensive programming approach that aligns with ATT&CK technique T1484.001, which involves modifying system parameters to maintain persistence or cause system instability. Organizations should also implement monitoring solutions to detect unusual network behavior that might indicate exploitation attempts or the presence of unpatched systems. Additionally, kernel hardening measures such as enabling CONFIG_STRICT_DEVMEM and implementing proper access controls for system configuration parameters can provide additional layers of defense against similar vulnerabilities in the networking subsystem. Regular kernel security auditing and vulnerability scanning should be conducted to identify and remediate similar race condition issues across the system infrastructure.