Description

Integer overflow or wraparound in .NET allows an unauthorized attacker to elevate privileges locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:05.287Z",
  "pubdate": "2026-08-11T17:18:05.287Z",
  "executiveSummary": "An integer overflow or wraparound vulnerability exists within .NET, enabling an unauthorized local attacker to successfully elevate privileges on affected systems. This vulnerability exposes core execution flows where numerical calculations regarding memory allocation, buffer sizing, or index tracking fail to properly validate boundary conditions.\nWhen subjected to maliciously crafted input or state conditions, the affected routines experience arithmetic wraparound, leading to memory corruption, improper access controls, or unintended execution states. The primary security impact is local privilege escalation, allowing a standard, low-privileged user to execute arbitrary code or commands with elevated privileges, potentially achieving full system compromise.\nThe attack vector is local, requiring the threat actor to have initial execution capability on the target machine. No complex network exposure or remote interaction is mandated, but successful exploitation relies on the ability to interact with vulnerable .NET components or applications executing on the host. Risk implications are severe in multi-tenant environments or systems where defense-in-depth relies on process isolation and least-privilege principles.",
  "technicalDetails": "The root cause of this vulnerability lies in insecure arithmetic operations within .NET internal components where integer values are handled without adequate bounds checking or overflow validation. Specifically, when inputs dictating buffer lengths, allocation sizes, or loop indices approach the maximum limit of their integer data type, subsequent arithmetic operations result in an integer wraparound.\nThis wraparound causes the allocated memory buffer to be significantly smaller than required by the downstream logic. Consequently, subsequent write operations trigger out-of-bounds memory writes or heap corruption.\nThe attack flow proceeds as follows: First, the local attacker provisions a crafted payload or interacts with a local .NET application designed to process inputs that trigger the vulnerable calculation. Second, the application passes these inputs to the vulnerable .NET component, initiating the arithmetic sequence. Third, the integer overflow occurs silently without raising an immediate exception, resulting in a severely truncated memory allocation size. Fourth, the routine attempts to write data into the undersized buffer, overwriting adjacent memory structures, function pointers, or critical control data structures.\nBy carefully controlling the overwritten memory regions, the attacker achieves arbitrary code execution within the context of the running process. If the vulnerable component executes with elevated privileges—such as a system service or a privileged daemon—the execution of arbitrary code directly facilitates local privilege escalation.\nThe vulnerability affects .NET runtimes and associated components where arithmetic safety is absent during internal indexing or sizing calculations. Exploitation requires local access, lack of proper input validation, and execution within a context capable of triggering the vulnerable code path."
}