CVE-2022-49798 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix race where eprobes can be called before the event
The flag that tells the event to call its triggers after reading the event is set for eprobes after the eprobe is enabled. This leads to a race where the eprobe may be triggered at the beginning of the event where the record information is NULL. The eprobe then dereferences the NULL record causing a NULL kernel pointer bug.
Test for a NULL record to keep this from happening.
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Analysis
by VulDB Data Team • 11/07/2025
The vulnerability described in CVE-2022-49798 resides within the Linux kernel's tracing subsystem, specifically affecting the event probe (eprobe) mechanism that is integral to kernel debugging and performance monitoring capabilities. This flaw represents a classic race condition scenario where timing dependencies between system operations create exploitable conditions. The issue manifests in the sequence of operations governing how eprobes interact with trace events, creating a window where the system can execute code paths before proper initialization has completed.
The technical root cause of this vulnerability stems from the improper ordering of flag setting operations within the kernel's tracing infrastructure. When eprobes are enabled, the mechanism that signals to the system to invoke associated triggers after event processing is configured after the eprobe itself becomes active. This temporal discrepancy creates a race condition where an eprobe can be triggered during the initial phase of event processing when record information remains uninitialized and set to NULL. The kernel's tracing framework attempts to process this NULL reference, leading to a NULL kernel pointer dereference that results in system instability or potential privilege escalation.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be exploited to gain unauthorized access to kernel memory spaces or cause denial of service conditions that compromise system integrity. Attackers can potentially leverage this race condition to execute arbitrary code with kernel privileges, making it particularly dangerous in environments where kernel-level monitoring and debugging are actively utilized. The vulnerability affects systems using the Linux kernel's tracing infrastructure, particularly those employing eprobe mechanisms for event monitoring and trigger execution.
This flaw aligns with CWE-362, which categorizes race conditions in concurrent systems, and demonstrates characteristics consistent with ATT&CK technique T1059.006 for kernel-mode rootkits and privilege escalation. The vulnerability's exploitation requires careful timing and understanding of the kernel's internal state management, making it suitable for sophisticated attacks targeting system security. The fix implemented addresses the core issue by introducing a NULL record check before proceeding with eprobe execution, effectively preventing the kernel from attempting to dereference uninitialized memory structures.
Mitigation strategies should prioritize applying the kernel patches released by the Linux kernel security team, which correct the race condition through proper synchronization mechanisms and conditional checks. System administrators should also implement monitoring for unusual tracing activity patterns that might indicate exploitation attempts. The fix demonstrates the importance of proper initialization sequencing in kernel code and reinforces the need for comprehensive testing of concurrent operations within critical system components. Organizations maintaining systems with active tracing capabilities should conduct thorough vulnerability assessments to ensure complete remediation and verify that no other similar race conditions exist within their kernel configurations.