Description

Out-of-bounds write in .NET allows an unauthorized attacker to execute code locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:19:12.640Z",
  "pubdate": "2026-08-11T17:19:12.640Z",
  "executiveSummary": "An out-of-bounds write vulnerability has been identified within .NET, representing a critical security flaw that exposes systems to local code execution. This vulnerability type arises when software writes data past the end, or before the beginning, of the intended buffer, frequently leading to memory corruption, arbitrary code execution, or application instability. The impact of this security defect is severe, as it allows an unauthorized attacker to achieve local code execution on the underlying operating system.\nThe affected product is .NET, impacting local system integrity and confidentiality. The risk implications are significant because successful exploitation grants malicious actors the ability to execute arbitrary commands or payloads within the security context of the victim user. Attacker capabilities include leveraging the memory corruption primitive to manipulate control flow or critical data structures in memory. Based on the provided vulnerability description, exploitation requires local access to the target system by an unauthorized attacker, indicating that the threat actor must already have a foothold or execution vector on the host to interact with the vulnerable .NET component.",
  "technicalDetails": "The root cause of this vulnerability is an out-of-bounds write condition residing within the memory management or data processing logic of the .NET runtime or associated libraries. Specifically, the vulnerable component fails to properly validate index boundaries or buffer sizes before performing memory write operations. This programming oversight permits input data or internal state manipulation to overflow allocated buffer boundaries, resulting in adjacent memory corruption.\nExploitation occurs when an unauthorized attacker leverages local execution capabilities to trigger the flawed code path within .NET. The attack flow typically involves supplying specially crafted inputs, parameters, or data structures that bypass boundary checks during processing. As the vulnerable function executes the write operation, data is written past the designated buffer limits into surrounding memory regions. Depending on the memory layout and the specific objects or function pointers residing adjacent to the target buffer, this overwrite can manipulate critical application data structures.\nRegarding authentication and privilege requirements, the vulnerability can be exploited by an unauthorized attacker operating locally, meaning standard user privileges may suffice depending on the specific execution context of the vulnerable .NET application. The attack vector is local, requiring the threat actor to execute code locally rather than over a network interface. Payload behavior following the successful memory corruption involves hijacking the instruction pointer or overwriting structured exception handling mechanisms to redirect execution flow to attacker-supplied shellcode or native payloads. The post-exploitation impact includes complete local system compromise, escalation of local privileges if running against a service with elevated permissions, persistence establishment, and arbitrary code execution on the host system."
}