# Microsoft Security Advisory CVE-2025-55248: .NET Information Disclosure Vulnerability Advisory record · `GHSA-gwq6-fmvp-qp68` - **Identifiers:** `GHSA-gwq6-fmvp-qp68` · `BIT-dotnet-2025-55248` · `BIT-dotnet-sdk-2025-55248` · `CVE-2025-55248` - **State:** Confirmed - **Severity:** CVSS 4.8 Medium - **Critical:** No - **Weakness (CWE):** [CWE-326](https://cwe.mitre.org/data/definitions/326.html) - **Tags:** [Weak cryptography or TLS](https://agentprime.io/advisories/tag/weak-crypto.md) - **Published:** 15 Oct 2025 - **Updated:** 10 Sept 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 15 Oct 2025, 17:39 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `Microsoft.NetCore.App.Runtime.linux-arm` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.linux-arm64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.linux-musl-arm` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.linux-musl-arm64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.linux-musl-x64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.linux-x64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.osx-arm64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.osx-x64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.win-arm` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.win-arm64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.win-x64` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` - `Microsoft.NetCore.App.Runtime.win-x86` (NuGet): affected `>=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `9.0.10`, `8.0.21` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > The Microsoft.NetCore.App.Runtime packages for linux, linux-musl, osx and win platforms (including arm, arm64, x64 and x86 variants) are affected in .NET 8.0 versions from 8.0.0 through 8.0.20 and .NET 9.0 versions from 9.0.0 through 9.0.9. A man-in-the-middle attacker can prevent TLS from being used between a client and an SMTP server, forcing the client to send data unencrypted. Upgrade to 8.0.21 or 9.0.10; no workaround is listed. Written 9 Nov 2026. ## Not analysed yet We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check. ## Severity and exploitation - 4.8 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C`, from CNA (microsoft) - **CISA KEV:** Not listed. - **EPSS:** 0.0074, the 54th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 14 Oct 2025, 22:11 UTC: [Published by the maintainers as a GitHub repository advisory](https://github.com/dotnet/runtime/security/advisories/GHSA-gwq6-fmvp-qp68) - 31 Oct 2026, 15:21 UTC: First seen by agentprime - 31 Oct 2026, 15:21 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-gwq6-fmvp-qp68) ## Sources - [GitHub Advisory Database: GHSA-gwq6-fmvp-qp68](https://github.com/advisories/GHSA-gwq6-fmvp-qp68) - [OSV: GHSA-gwq6-fmvp-qp68](https://osv.dev/vulnerability/GHSA-gwq6-fmvp-qp68) - - - - - Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .