CVE-2026-54000 in osquery
Summary
by MITRE • 07/10/2026
osquery is a SQL powered operating system instrumentation, monitoring, and analytics framework. Prior to 5.23.1, on Windows, a local unprivileged attacker can cause a heap buffer out-of-bounds write if there is a query of the processes table targeting a maliciously crafted process, due to unchecked PEB string lengths in process command-line and current-directory reads. If exploited successfully, this could allow a potential local privilege escalation from standard user to SYSTEM. This issue is fixed in version 5.23.1.
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Analysis
by VulDB Data Team • 07/10/2026
The vulnerability affects osquery version prior to 5231 on Windows platforms where a heap buffer out-of-bounds write condition exists due to improper validation of Process Environment Block (PEB) string lengths during process command-line and current directory reads from the processes table. This flaw represents a critical security weakness that enables local privilege escalation from standard user to SYSTEM level privileges.
The technical root cause stems from unchecked PEB string length validation within osquery's Windows implementation where maliciously crafted process data can trigger buffer overflows during memory operations. When querying the processes table, the system reads command-line arguments and current working directory information directly from the Process Environment Block without proper bounds checking on string lengths. This allows an attacker to manipulate process metadata in such a way that exceeds allocated buffer boundaries during memory copy operations, resulting in heap corruption.
The operational impact of this vulnerability is severe as it provides a direct path for local attackers to escalate privileges without requiring elevated access initially. The flaw specifically targets the Windows operating system's process enumeration capabilities where osquery accesses PEB structures to gather process information. Attackers can exploit this by creating malicious processes with oversized command-line arguments or directory paths that, when queried through osquery's processes table, trigger the buffer overflow condition. The heap corruption can potentially be leveraged to execute arbitrary code with SYSTEM privileges, effectively bypassing standard user access controls.
This vulnerability maps directly to CWE-121 Heap-based Buffer Overflow and aligns with ATT&CK technique T1068, which covers Local Privilege Escalation through exploitation of software vulnerabilities. The flaw demonstrates a classic buffer overflow pattern where insufficient input validation leads to memory corruption that can be exploited for privilege escalation. The Windows-specific nature of the issue relates to the PEB structure implementation within the Windows kernel and how osquery interfaces with these low-level process management APIs.
Organizations should immediately upgrade to osquery version 5231 or later to remediate this vulnerability. System administrators should also implement monitoring for unusual process enumeration activities that might indicate exploitation attempts. Additional mitigations include restricting access to osquery execution capabilities, implementing proper access controls on system resources, and conducting regular security assessments of instrumentation tools. The fix in version 5231 addresses the core issue by implementing proper bounds checking on PEB string lengths during process data extraction operations, preventing the heap buffer overflow condition from occurring during normal query processing.