# CVE-2026-58649: .NET Information Disclosure Vulnerability > An origin validation error in .NET allows unauthorized attackers to disclose information over a network. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/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:** 8 Sep 2026 - **Updated:** 14 Oct 2026 - **Also known as:** ALSA-2026:67524, ALSA-2026:67525, ALSA-2026:68316, BELL-CVE-2026-58649, GHSA-44g5-m8vm-448v, RHSA-2026:67524, RHSA-2026:67525, RHSA-2026:68316, RHSA-2026:76978, RHSA-2026:77004, RLSA-2026:67524, RLSA-2026:67525, RLSA-2026:68316, UBUNTU-CVE-2026-58649 ## What is CVE-2026-58649? CVE-2026-58649 is a medium-severity vulnerability in Microsoft .Net, published on 8 Sep 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 Origin validation error in .NET allows an unauthorized attacker to disclose information over a network. Weakness: CWE-346 (Origin Validation Error) ## Which versions are affected by CVE-2026-58649? It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `aspnetcore-runtime-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `aspnetcore-runtime-dbg-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `aspnetcore-targeting-pack-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `dotnet-apphost-pack-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `dotnet-hostfxr-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `dotnet-runtime-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `dotnet-runtime-dbg-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `dotnet-sdk-8.0` | AlmaLinux:10 | All versions | 8.0.131-1.el10_2 | | `dotnet-sdk-8.0-source-built-artifacts` | AlmaLinux:10 | All versions | 8.0.131-1.el10_2 | | `dotnet-sdk-dbg-8.0` | AlmaLinux:10 | All versions | 8.0.131-1.el10_2 | | `dotnet-targeting-pack-8.0` | AlmaLinux:10 | All versions | 8.0.31-1.el10_2 | | `dotnet-templates-8.0` | AlmaLinux:10 | All versions | 8.0.131-1.el10_2 | | `aspnetcore-runtime-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `aspnetcore-runtime-dbg-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `aspnetcore-targeting-pack-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `dotnet-apphost-pack-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `dotnet-hostfxr-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `dotnet-runtime-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `dotnet-runtime-dbg-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `dotnet-sdk-8.0` | AlmaLinux:8 | All versions | 8.0.131-1.el8_10 | | `dotnet-sdk-8.0-source-built-artifacts` | AlmaLinux:8 | All versions | 8.0.131-1.el8_10 | | `dotnet-sdk-dbg-8.0` | AlmaLinux:8 | All versions | 8.0.131-1.el8_10 | | `dotnet-targeting-pack-8.0` | AlmaLinux:8 | All versions | 8.0.31-1.el8_10 | | `dotnet-templates-8.0` | AlmaLinux:8 | All versions | 8.0.131-1.el8_10 | | `aspnetcore-runtime-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `aspnetcore-runtime-dbg-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `aspnetcore-targeting-pack-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `dotnet-apphost-pack-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `dotnet-hostfxr-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `dotnet-runtime-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `dotnet-runtime-dbg-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `dotnet-sdk-8.0` | AlmaLinux:9 | All versions | 8.0.131-1.el9_8 | | `dotnet-sdk-8.0-source-built-artifacts` | AlmaLinux:9 | All versions | 8.0.131-1.el9_8 | | `dotnet-sdk-dbg-8.0` | AlmaLinux:9 | All versions | 8.0.131-1.el9_8 | | `dotnet-targeting-pack-8.0` | AlmaLinux:9 | All versions | 8.0.31-1.el9_8 | | `dotnet-templates-8.0` | AlmaLinux:9 | All versions | 8.0.131-1.el9_8 | | `aspnetcore-runtime-8.0` | Red Hat:enterprise_linux:10.2 | All versions | 0:8.0.31-1.el10_2 | | `aspnetcore-runtime-dbg-8.0` | Red Hat:enterprise_linux:10.2 | All versions | 0:8.0.31-1.el10_2 | | `aspnetcore-targeting-pack-8.0` | Red Hat:enterprise_linux:10.2 | All versions | 0:8.0.31-1.el10_2 | | `dotnet-apphost-pack-8.0` | Red Hat:enterprise_linux:10.2 | All versions | 0:8.0.31-1.el10_2 | Products: Microsoft .Net, Microsoft .Net Sdk, Microsoft Visual Studio 2022, Microsoft Visual Studio 2026. ## How do I fix CVE-2026-58649? Apply the vendor's patch. ## Is CVE-2026-58649 being exploited? There is no known exploitation of CVE-2026-58649 in the wild and no public exploit code. ## Other vulnerabilities in Microsoft .Net - [CVE-2024-43498](https://insights.sbomify.com/CVE-2024-43498/): .NET and Visual Studio Remote Code Execution Vulnerability (critical 9.8) - [CVE-2024-0057](https://insights.sbomify.com/CVE-2024-0057/): NET, .NET Framework, and Visual Studio Security Feature Bypass Vulnerability (critical 9.1) - [CVE-2026-96957](https://insights.sbomify.com/CVE-2026-96957/): .NET Security Feature Bypass Vulnerability (high 8.8) - [CVE-2026-69439](https://insights.sbomify.com/CVE-2026-69439/): .NET and Visual Studio Elevation of Privilege Vulnerability (high 8.8) - [CVE-2026-71328](https://insights.sbomify.com/CVE-2026-71328/): .NET and Visual Studio Remote Code Execution Vulnerability (high 8.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-58649 and fix it if it is affected. What it is: CVE-2026-58649 is a medium-severity vulnerability in Microsoft .Net, published on 8 Sep 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-2026-58649 in the wild and no public exploit code. Affected product: Microsoft .Net. No package-level version data is available, so check the vendor advisory linked from the reference page. 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-2026-58649/ (Markdown: https://insights.sbomify.com/CVE-2026-58649/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58649 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58649 - OSV: https://osv.dev/vulnerability/CVE-2026-58649 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-58649/ Summaries are generated and may contain mistakes; the official description above is the record.