Description

Integer overflow or wraparound in .NET Framework allows an unauthorized attacker to execute code locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.0",
  "pubDate": "2026-08-11T17:18:43.850Z",
  "pubdate": "2026-08-11T17:18:43.850Z",
  "executiveSummary": "An integer overflow or wraparound vulnerability exists within the .NET Framework, posing significant risk to system integrity and security. This vulnerability enables an unauthorized local attacker to achieve arbitrary code execution on targeted systems.\nThe flaw stems from improper handling of integer boundaries during arithmetic operations within affected components of the .NET Framework. When an integer operation exceeds the maximum storable value, a wraparound condition occurs, leading to memory corruption, incorrect buffer allocation logic, or out-of-bounds memory manipulation.\nThe primary impact of successful exploitation is the execution of arbitrary native or managed code under the security context of the currently logged-on user or the application process. Depending on the privilege level of the targeted process, this could result in local privilege escalation or complete system compromise.\nAffected systems include deployments utilizing vulnerable versions of the .NET Framework. Exploitation requires local access to the target host and typically involves tricking a user or application into processing a specially crafted input, file, or data stream that triggers the integer overflow condition.\nGiven the capability for arbitrary code execution, organizations must prioritize remediation through official vendor patches and apply defensive hardening measures to restrict unauthorized local execution and minimize potential attack surfaces.",
  "technicalDetails": "The root cause of the vulnerability resides in unsafe arithmetic operations implemented within specific internal functions and parsing routines of the .NET Framework. Specifically, when calculating buffer sizes, memory offsets, or array dimensions, the application fails to adequately validate input parameters against maximum integer limits.\nThis absence of boundary checks allows an attacker to supply inputs designed to induce an integer overflow or wraparound. Upon overflow, the allocated buffer size wraps around to a significantly smaller value than required, while the subsequent memory write or copy operation attempts to write the full, intended data size into the undersized buffer.\nThis memory corruption manifests as a classic heap-based or stack-based buffer overflow condition. Step-by-step, exploitation occurs as follows: first, the local attacker crafts a malicious payload or input vector containing values calculated to trigger the integer wrap condition during processing by the .NET Framework component. Second, the attacker delivers this payload locally, either by invoking a vulnerable application directly or by placing the payload where a privileged or automated .NET application will process it.\nThird, the vulnerable function evaluates the size parameters, resulting in an integer overflow and subsequent under-allocation of memory resources. Fourth, the application proceeds to copy or write data into the restricted buffer, overwriting adjacent memory structures, function pointers, or critical execution control data.\nFinally, by carefully controlling the contents of the overflow, the attacker overwrites return addresses or execution pointers, redirecting the control flow to malicious shellcode or leveraging native execution primitives to execute arbitrary code within the address space of the target process.\nRegarding execution constraints, the vulnerability requires local access to the system. No network exposure is inherently required unless the vulnerable .NET application exposes a local IPC mechanism or service accessible to the attacker. Authentication and privilege requirements depend on the execution context of the targeted application, though standard local execution privileges are typically sufficient to initiate the attack flow against user-space applications."
}