# CVE-2026-102870: ASP.NET Core Remote Code Execution Vulnerability

> An unauthorized attacker can execute arbitrary code over the network via improper code generation in ASP.NET Core.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 13 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-g27p-qf6j-c96c, UBUNTU-CVE-2026-102870

## What is CVE-2026-102870?

CVE-2026-102870 is a high-severity code injection vulnerability in Microsoft .NET 10.0 installed on Linux, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Improper control of generation of code ('code injection') in ASP.NET Core allows an unauthorized attacker to execute code over a network.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-102870?

4 open source packages ship an affected version, including Microsoft.AspNetCore.Components.WebAssembly.Server.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Microsoft.AspNetCore.Components.WebAssembly.Server` | NuGet | From 10.0.0 | 10.0.13 |
| `Microsoft.AspNetCore.Components.WebAssembly.Server` | NuGet | From 10.0.0 | 10.0.13 |
| `Microsoft.AspNetCore.Components.WebAssembly.Server` | NuGet | From 11.0.0-preview.1 | 11.0.0-rc.2.26478.115 |
| `Microsoft.AspNetCore.Components.WebAssembly.Server` | NuGet | From 11.0.0-preview.1 | 11.0.0-rc.2.26478.115 |

## How do I fix CVE-2026-102870?

Upgrade Microsoft.AspNetCore.Components.WebAssembly.Server to a fixed version for your release line: 10.0.13 or 11.0.0-rc.2.26478.115.

## Is CVE-2026-102870 being exploited?

There is no known exploitation of CVE-2026-102870 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102870 and fix it if it is affected.

What it is: CVE-2026-102870 is a high-severity code injection vulnerability in Microsoft .NET 10.0 installed on Linux, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-102870 in the wild and no public exploit code.

Affected packages and fixed versions:
- Microsoft.AspNetCore.Components.WebAssembly.Server (NuGet): affected from 10.0.0; fixed in 10.0.13
- Microsoft.AspNetCore.Components.WebAssembly.Server (NuGet): affected from 10.0.0; fixed in 10.0.13
- Microsoft.AspNetCore.Components.WebAssembly.Server (NuGet): affected from 11.0.0-preview.1; fixed in 11.0.0-rc.2.26478.115
- Microsoft.AspNetCore.Components.WebAssembly.Server (NuGet): affected from 11.0.0-preview.1; fixed in 11.0.0-rc.2.26478.115

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-102870/ (Markdown: https://insights.sbomify.com/CVE-2026-102870/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102870
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102870
- OSV: https://osv.dev/vulnerability/CVE-2026-102870

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102870/
Summaries are generated and may contain mistakes; the official description above is the record.