CVE-2022-49602 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
ip: Fix a data-race around sysctl_fwmark_reflect.
While reading sysctl_fwmark_reflect, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.
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Analysis
by VulDB Data Team • 06/12/2025
The vulnerability identified as CVE-2022-49602 represents a critical data race condition within the Linux kernel's networking subsystem, specifically affecting the ip module's handling of the sysctl_fwmark_reflect parameter. This issue arises from insufficient synchronization mechanisms when multiple threads attempt to access and modify the same memory location simultaneously, creating a scenario where concurrent read and write operations can lead to unpredictable behavior and potential system instability.
The technical flaw manifests in the improper handling of the sysctl_fwmark_reflect variable, which controls how firewall mark reflections are processed in the kernel's network stack. When a reader process attempts to access this parameter while another process modifies it concurrently, the system experiences a classic race condition where the reader may observe inconsistent or partially updated data. This vulnerability falls under the CWE-362 category of Concurrent Execution using Shared Resource with Unprotected Read-Write Access, representing a fundamental concurrency control failure in kernel space operations.
The operational impact of this vulnerability extends beyond simple data corruption, potentially enabling malicious actors to exploit the race condition for privilege escalation or denial-of-service attacks. Attackers could manipulate the concurrent access patterns to trigger undefined behavior in the kernel's networking code, potentially leading to system crashes or unauthorized access to network processing capabilities. The vulnerability directly affects systems relying on advanced firewall mark processing and could compromise the integrity of network traffic handling in multi-threaded environments.
Mitigation strategies should focus on implementing proper memory barrier operations using READ_ONCE() macro as recommended in the patch resolution. This approach ensures that readers consistently observe the complete value of the sysctl_fwmark_reflect parameter without interference from concurrent writers. System administrators should prioritize applying the kernel patches containing the fix, while organizations should implement monitoring solutions to detect anomalous network behavior that might indicate exploitation attempts. The fix aligns with ATT&CK technique T1059.003 for kernel-level persistence mechanisms and represents a critical security update for enterprise environments running Linux kernel versions affected by this race condition.