CVE-2022-42432 in Linux
Summary
by MITRE • 03/29/2023
This vulnerability allows local attackers to disclose sensitive information on affected installations of the Linux Kernel 6.0-rc2. An attacker must first obtain the ability to execute high-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the nft_osf_eval function. The issue results from the lack of proper initialization of memory prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the kernel. Was ZDI-CAN-18540.
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Analysis
by VulDB Data Team • 08/18/2026
The vulnerability identified as CVE-2023-ZDI-CAN-18540 represents a critical security flaw within the Linux Kernel, specifically affecting versions 6.0-rc2 and potentially earlier releases depending on code lineage. This issue is categorized under CWE-908, which denotes the use of uninitialized resource, or more broadly CWE-457 regarding the use of an uninitialized variable. The core technical defect resides in the nft_osf_eval function, a component responsible for evaluating object set filters within the Netfilter subsystem. In this specific context, the kernel fails to properly initialize memory buffers before they are accessed and utilized during packet processing operations. This lack of initialization means that the memory contains residual data from previous allocations or stack contents, which can include sensitive information such as cryptographic keys, session tokens, or other privileged data structures residing in adjacent memory locations.
From an operational perspective, this vulnerability allows for local privilege escalation if combined with additional exploitation techniques. While a direct exploit requires the attacker to already possess high-privileged code execution capabilities on the target system, the disclosed uninitialized memory can serve as a powerful information leak vector. By reading these uninitialized values, an attacker may gain insights into kernel internal states or bypass certain security controls that rely on randomization or secure initialization practices. The impact is compounded by the fact that Netfilter operates at the network stack level, meaning successful exploitation could potentially influence how packets are processed and filtered, although the primary risk here remains information disclosure leading to further privilege escalation when chained with other vulnerabilities such as race conditions or buffer overflows.
The attack vector for this vulnerability aligns with MITRE ATT&CK technique T1059, specifically Command and Scripting Interpreter scenarios where local access is leveraged to execute arbitrary code in the context of the kernel. The requirement for an attacker to first obtain high-privileged execution rights indicates that this flaw is typically part of a multi-stage attack chain rather than a standalone remote exploit. However, its presence significantly lowers the barrier for privilege escalation once initial foothold is achieved through other means such as web application vulnerabilities or misconfigured services.
Mitigation strategies primarily involve applying vendor-provided kernel patches that address the memory initialization oversight within the nft_osf_eval function. System administrators should ensure their systems are updated to a version of the Linux Kernel where this specific uninitialized variable issue has been resolved, typically by ensuring all variables and buffers are explicitly zeroed or initialized before use in network filtering operations. Additionally, implementing strict access controls and monitoring for unusual kernel-level activities can help detect attempts to leverage such vulnerabilities in conjunction with other exploits. Regular security audits focusing on Netfilter configurations and kernel module integrity further reduce the attack surface associated with this class of memory safety issues.