CVE-2018-8087 in Linux
Summary
by MITRE
Memory leak in the hwsim_new_radio_nl function in drivers/net/wireless/mac80211_hwsim.c in the Linux kernel through 4.15.9 allows local users to cause a denial of service (memory consumption) by triggering an out-of-array error case.
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Analysis
by VulDB Data Team • 09/14/2025
The vulnerability identified as CVE-2018-8087 represents a critical memory management flaw within the Linux kernel's wireless networking subsystem, specifically affecting the mac80211 hardware simulator component. This issue resides in the hwsim_new_radio_nl function located in drivers/net/wireless/mac80211_hwsim.c, where improper error handling leads to memory allocation without subsequent deallocation. The vulnerability manifests when local users can trigger an out-of-array error case through crafted input parameters, causing the kernel to allocate memory resources that are never properly released. This memory leak occurs in the context of wireless hardware simulation, which is commonly used for testing and development purposes within the kernel's networking stack. The flaw is particularly concerning as it affects kernel versions up to and including 4.15.9, representing a substantial portion of the kernel release cycle that many organizations continue to utilize in production environments.
The technical implementation of this vulnerability stems from inadequate memory management practices within the wireless hardware simulator's network layer handling function. When the hwsim_new_radio_nl function encounters an out-of-array error condition, the code path fails to properly clean up allocated memory resources, resulting in a gradual accumulation of unreleased memory blocks. This memory leak directly violates the principles of proper resource management as outlined in CWE-401, which specifically addresses memory leaks in software systems. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited by any local user with access to the system, regardless of their privilege level. The out-of-array error case creates a scenario where memory allocation occurs but subsequent deallocation logic is bypassed due to early function returns or error handling that does not account for all possible execution paths.
The operational impact of this memory leak vulnerability extends beyond simple resource exhaustion, creating potential for significant system instability and performance degradation. As memory consumption gradually increases through repeated exploitation attempts, the affected system experiences progressive memory pressure that can eventually lead to system crashes or complete denial of service conditions. This type of vulnerability aligns with ATT&CK technique T1499.001, which covers resource exhaustion attacks targeting system memory. The local privilege escalation aspect means that any user with access to the system can potentially trigger this condition, making it a particularly attractive target for attackers seeking to disrupt services without requiring elevated privileges. Organizations running affected kernel versions face the risk of sustained performance degradation, increased system latency, and potential service interruptions that can affect network connectivity and overall system responsiveness.
Mitigation strategies for CVE-2018-8087 must focus on both immediate patching and operational security measures. The most effective solution involves upgrading to kernel versions that contain the appropriate fix, which was implemented in kernel versions 4.15.10 and later. System administrators should prioritize patching critical systems and implementing a comprehensive kernel update strategy across their infrastructure. In environments where immediate patching is not feasible, administrators can consider implementing kernel lockdown mechanisms or restricting access to wireless hardware simulation interfaces to limit potential exploitation vectors. Monitoring for unusual memory consumption patterns and implementing automated alerting for memory leaks can help detect exploitation attempts before they result in significant system impact. The vulnerability also underscores the importance of proper code review processes and thorough testing of error handling paths, particularly in kernel-level code where resource management failures can have cascading effects on system stability and security posture.