{"answers":{"affected":"8 open source packages ship an affected version, including System.Security.Cryptography.Cose, dotnet and dotnet-sdk. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-21218 in the wild and no public exploit code.","fix":"Upgrade System.Security.Cryptography.Cose to a fixed version for your release line: 10.0.3, 8.0.2 or 9.0.13.","what":"CVE-2026-21218 is a high-severity vulnerability in Microsoft .Net, published on 10 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-21218 and fix it if it is affected.\n\nWhat it is: CVE-2026-21218 is a high-severity vulnerability in Microsoft .Net, published on 10 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-21218 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- System.Security.Cryptography.Cose (NuGet): affected from 10.0.0; fixed in 10.0.3\n- System.Security.Cryptography.Cose (NuGet): affected from 10.0.0; fixed in 10.0.3\n- System.Security.Cryptography.Cose (NuGet): affected from 8.0.0; fixed in 8.0.2\n- System.Security.Cryptography.Cose (NuGet): affected from 8.0.0; fixed in 8.0.2\n- System.Security.Cryptography.Cose (NuGet): affected from 9.0.0; fixed in 9.0.13\n- System.Security.Cryptography.Cose (NuGet): affected from 9.0.0; fixed in 9.0.13\n- dotnet (Bitnami): affected from 8.0.0; fixed in 8.0.24, 9.0.13, 10.0.3\n- dotnet-sdk (Bitnami): affected from 8.0.0; fixed in 8.0.24, 9.0.13, 10.0.3\n\nTask:\n1. 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.\n2. 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.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-21218/ (Markdown: https://insights.sbomify.com/CVE-2026-21218/index.md)","id":"CVE-2026-21218","markdown":"https://insights.sbomify.com/CVE-2026-21218/index.md","name":"CVE-2026-21218","record":{"aliases":["BELL-CVE-2026-21218","BIT-dotnet-2026-21218","BIT-dotnet-sdk-2026-21218","GHSA-qvhc-9v3j-5rfw","MINI-6wgc-8xfm-5x6v","MINI-jpv7-469r-894p","UBUNTU-CVE-2026-21218","USN-8025-1","USN-8025-2"],"analysis":{"component_type":"library","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":".NET runtime","requires_auth":"none","summary":"An attacker can perform network spoofing due to improper handling of missing special elements in the .NET runtime.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"microsoft","cpe":[{"product":".net","vendor":"microsoft"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C","version":"3.1"},"cwes":[{"id":"CWE-166","name":"Improper Handling of Missing Special Element"}],"description":"Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.","ecosystems":["Bitnami","NuGet"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":".NET Spoofing Vulnerability","id":"CVE-2026-21218","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Bitnami","product":"microsoft:.net","products":["microsoft:.net"],"type":"security_feature_bypass","year":"2026"},"n_packages":8,"n_references":1,"next":{"headline":"Inbox COM Objects (Global Memory) Remote Code Execution Vulnerability","id":"CVE-2026-21219"},"packages":[{"ecosystem":"Bitnami","fixed":["8.0.24","9.0.13","10.0.3"],"introduced":["8.0.0","9.0.0","10.0.0"],"last_affected":[],"package":"dotnet","purl":"pkg:bitnami/dotnet","source":"BIT-dotnet-2026-21218"},{"ecosystem":"Bitnami","fixed":["8.0.24","9.0.13","10.0.3"],"introduced":["8.0.0","9.0.0","10.0.0"],"last_affected":[],"package":"dotnet-sdk","purl":"pkg:bitnami/dotnet-sdk","source":"BIT-dotnet-sdk-2026-21218"},{"ecosystem":"NuGet","fixed":["10.0.3"],"introduced":["10.0.0"],"last_affected":[],"package":"System.Security.Cryptography.Cose","purl":null,"source":"GHSA-qvhc-9v3j-5rfw"},{"ecosystem":"NuGet","fixed":["10.0.3"],"introduced":["10.0.0"],"last_affected":[],"package":"System.Security.Cryptography.Cose","purl":"pkg:nuget/System.Security.Cryptography.Cose","source":"GHSA-qvhc-9v3j-5rfw"},{"ecosystem":"NuGet","fixed":["8.0.2"],"introduced":["8.0.0"],"last_affected":[],"package":"System.Security.Cryptography.Cose","purl":null,"source":"GHSA-qvhc-9v3j-5rfw"},{"ecosystem":"NuGet","fixed":["8.0.2"],"introduced":["8.0.0"],"last_affected":[],"package":"System.Security.Cryptography.Cose","purl":"pkg:nuget/System.Security.Cryptography.Cose","source":"GHSA-qvhc-9v3j-5rfw"},{"ecosystem":"NuGet","fixed":["9.0.13"],"introduced":["9.0.0"],"last_affected":[],"package":"System.Security.Cryptography.Cose","purl":null,"source":"GHSA-qvhc-9v3j-5rfw"},{"ecosystem":"NuGet","fixed":["9.0.13"],"introduced":["9.0.0"],"last_affected":[],"package":"System.Security.Cryptography.Cose","purl":"pkg:nuget/System.Security.Cryptography.Cose","source":"GHSA-qvhc-9v3j-5rfw"}],"prev":{"headline":"Improper input validation in Bixby prior to version 4.0.85.6 allows privileged local attackers to launch arbitrary activity.","id":"CVE-2026-21157"},"products":[".NET 10.0",".NET 8.0",".NET 9.0"],"published":"2026-02-10","related":[{"cvss_score":9.8,"headline":".NET and Visual Studio Remote Code Execution Vulnerability","id":"CVE-2024-43498","kev_date_added":null,"published":"2024-11-12"},{"cvss_score":9.1,"headline":"NET, .NET Framework, and Visual Studio Security Feature Bypass Vulnerability","id":"CVE-2024-0057","kev_date_added":null,"published":"2024-01-09"},{"cvss_score":8.8,"headline":".NET Security Feature Bypass Vulnerability","id":"CVE-2026-96957","kev_date_added":null,"published":"2026-10-13"},{"cvss_score":8.8,"headline":".NET and Visual Studio Elevation of Privilege Vulnerability","id":"CVE-2026-69439","kev_date_added":null,"published":"2026-09-08"},{"cvss_score":8.8,"headline":".NET and Visual Studio Remote Code Execution Vulnerability","id":"CVE-2026-71328","kev_date_added":null,"published":"2026-09-08"},{"cvss_score":8.8,"headline":"ASP.NET Core Elevation of Privilege Vulnerability","id":"CVE-2026-47300","kev_date_added":null,"published":"2026-07-14"},{"cvss_score":8.8,"headline":"ASP.NET Core Elevation of Privilege Vulnerability","id":"CVE-2026-47303","kev_date_added":null,"published":"2026-07-14"}],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"Bitnami","prefix":"BIT"},{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-19","vendors":["Microsoft"]},"summary":"An attacker can perform network spoofing due to improper handling of missing special elements in the .NET runtime.","url":"https://insights.sbomify.com/CVE-2026-21218/"}