CVE-2026-62886

This is a bug in .NET (the code framework many Windows tools and apps use). If someone already has local access and can interact with the system, the bug can let them gain much higher permissions than they should. Think of it like finding a hidden “reset to administrator” switch inside a toolchain—if the right part of the tool is loaded and someone is already on the machine, they can pull it.

This matters if you use .NET and Visual Studio 2022/2026 on Windows, especially on machines where code using the vulnerable .NET components gets loaded into memory. A successful attack requires a local user (not a remote internet attack) and requires user interaction, so it’s mainly a risk for developer workstations, build machines, or any system an attacker can get to locally. Reachability is limited to situations where the vulnerable .NET code is loaded into memory on a machine the attacker can access locally.

This should be treated as RED because the vulnerability can let an attacker go from local access to full control of the system, which is the kind of escalation that leads to real damage. Even though there’s no clear dated public exploitation report and no public exploit code on record, the patch is available and the risk is high for environments where developer machines can be reached by untrusted insiders or compromised accounts. Also note this is press-associated with Lazarus group activity.

1. Confirm likely exposure.
   • Identify whether the organization uses any of the affected platforms: Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.8, and/or the .NET runtimes named in the fix list (.NET 8.0, .NET 9.0, .NET 10.0, plus the generic “.net” track).
   • Determine the exact installed version/build numbers.
2. Check for vulnerable versions.
   • Visual Studio 2022 is vulnerable if it is not yet at 17.14.38.
   • Visual Studio 2026 is vulnerable if it is not yet at 18.8.3.
   • .NET is vulnerable if your installed runtime is not yet at 8.0.30.
   • .NET 9.0 is vulnerable if your installed runtime is not yet at 9.0.19.
   • .NET 10.0 is vulnerable if your installed runtime is not yet at 10.0.11.
3. Apply the fixed versions.
   • Upgrade Visual Studio 2022 to 17.14.38.
   • Upgrade Visual Studio 2026 to 18.8.3.
   • Upgrade .NET 8.0 (and the “.net” track) to 8.0.30.
   • Upgrade .NET 9.0 to 9.0.19.
   • Upgrade .NET 10.0 to 10.0.11.
4. If patching is delayed (temporary containment).
   • Limit local access to developer/build machines (reduce the chance an attacker gets local user access).
   • Restrict who can run interactive tasks on those machines, and monitor for suspicious local activity.
   • Focus on machines where the vulnerable .NET code is loaded into memory (developer sessions that load the affected components).
5. What to monitor after updating.
   • Confirm the update succeeded by re-checking version/build numbers.
   • Review logs for unusual privilege changes or unexpected administrative behavior from local accounts.
6. KEV status.
   • This CVE is not currently listed in CISA KEV, so treat this as a high-priority patch based on the vulnerability impact and available fixes, rather than as confirmed systemwide known exploitation.

CVE-2026-62886 is a high-severity local elevation of privilege in .NET (CWE-122 integer overflow, CWE-190 integer overflow issues) where an integer overflow/wraparound enables unauthorized high-impact actions once the vulnerable .NET code/library is loaded into memory. The attack is Local Access and requires user interaction, so it is not a direct internet-exposed remote flaw. Exploitation is not clearly confirmed via dated reporting in the provided findings, and there is no public exploit code recorded, but press attention links it to Lazarus group activity. No KEV listing was provided. A patch is available across Visual Studio 2022/2026 and .NET runtime lines with fixed versions specified in the patch findings. (EPSS was provided only as a prediction and is not used to drive the urgency decision here.)