# Microsoft Security Advisory CVE-2025-55315: .NET Security Feature Bypass Vulnerability Advisory record · `GHSA-5rrx-jjjq-q2r5` - **Identifiers:** `GHSA-5rrx-jjjq-q2r5` · `BIT-aspnet-core-2025-55315` · `CVE-2025-55315` - **State:** Confirmed - **Severity:** CVSS 9.9 Critical - **Critical:** Yes: CVSS 9+, CVSS 7+ and EPSS - **Weakness (CWE):** [CWE-444](https://cwe.mitre.org/data/definitions/444.html) - **Tags:** [HTTP request smuggling](https://agentprime.io/advisories/tag/request-smuggling.md) - **Published:** 14 Oct 2025 - **Updated:** 10 Sept 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 14 Oct 2025, 20:32 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Critical Critical, because: - CVSS score 9.9: 9.0 or more. - CVSS score 9.9 (7.0 or more) and EPSS 0.67 (0.1 or more): a high score and a real chance of exploitation in the next 30 days. How we decide what’s critical: ## Affected packages - `Microsoft.AspNetCore.Server.Kestrel.Core` (NuGet): affected `<2.3.6`; fixed in `2.3.6` - `Microsoft.AspNetCore.App.Runtime.linux-arm` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.linux-arm64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.linux-musl-arm` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.linux-musl-arm64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.linux-musl-x64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.linux-x64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.osx-arm64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.osx-x64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.win-arm` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.win-arm64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.win-x64` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` - `Microsoft.AspNetCore.App.Runtime.win-x86` (NuGet): affected `>=10.0.0-rc.1.25451.107, <10.0.0-rc.2.25502.107 || >=9.0.0, <9.0.10 || >=8.0.0, <8.0.21`; fixed in `10.0.0-rc.2.25502.107`, `9.0.10`, `8.0.21` ## 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 - 9.9 Critical, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L/E:U/RL:O/RC:C`, from CNA (microsoft) - **CISA KEV:** Not listed. - **EPSS:** 0.67, the 99th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 31 Oct 2026, 15:21 UTC: First seen by agentprime - 31 Oct 2026, 15:21 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-5rrx-jjjq-q2r5) ## Sources - [GitHub Advisory Database: GHSA-5rrx-jjjq-q2r5](https://github.com/advisories/GHSA-5rrx-jjjq-q2r5) - [OSV: GHSA-5rrx-jjjq-q2r5](https://osv.dev/vulnerability/GHSA-5rrx-jjjq-q2r5) - - - - - 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: .