{"id":"CVE-2026-50659","title":".NET Spoofing Vulnerability","summary":"Improper encoding or escaping of output in .NET allows an authorized attacker to perform spoofing over a network.","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C","cvssSource":"cna","cwe":["CWE-116"],"vendor":"Microsoft","product":".NET 10.0","affected":[".net_10.0 >= 10.0.0 < 10.0.10",".net_8.0 >= 8.0.0 < 8.0.29",".net_9.0 >= 9.0.0 < 9.0.18",".net_framework_3.5 >= 3.5.0 < 2.0.50727.8983 & 3.0.30729.8978",".net_framework_3.5_and_4.7.2 >= 4.7.0 < 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0",".net_framework_3.5_and_4.8 >= 4.8.0 < 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0",".net_framework_3.5_and_4.8.1 >= 4.8.1 < 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0",".net_framework_4.6.2_4.7_4.7.1_4.7.2 >= 4.7.0 < 4.7.4143.0",".net_framework_4.8 >= 4.8.0 < 4.8.4803.0",".net_framework_4.8.1 >= 4.8.0.0 < 4.8.9340.0","visual_studio_2022_version_17.12 >= 17.12.0 < 17.12.22","visual_studio_2022_version_17.14 >= 17.14.0 < 17.14.36","visual_studio_2026_version_18.7 >= 18.0 < 18.7.4"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-07-14T20:32:29.416499Z"},"published":"2026-07-14","updated":"2026-09-17","sourceUpdated":"2026-09-17T22:32:09.851Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-50659","references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50659","label":".NET Spoofing Vulnerability"},{"url":"https://github.com/dotnet/runtime/security/advisories/GHSA-74jp-vm22-8q8x"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50659"},{"url":"https://github.com/dotnet/announcements/issues/423"},{"url":"https://github.com/dotnet/runtime/issues/130716"},{"url":"https://github.com/advisories/GHSA-74jp-vm22-8q8x"}],"tags":["cve.org","ghsa","nuget"],"epss":0.0055,"epssPercentile":0.4465,"aliases":["GHSA-74jp-vm22-8q8x"],"ecosystem":"nuget","patched":["Microsoft.NetCore.App.Runtime.linux-arm 10.0.10","Microsoft.NetCore.App.Runtime.linux-arm64 10.0.10","Microsoft.NetCore.App.Runtime.linux-musl-arm 10.0.10","Microsoft.NetCore.App.Runtime.linux-musl-arm64 10.0.10","Microsoft.NetCore.App.Runtime.linux-musl-x64 10.0.10","Microsoft.NetCore.App.Runtime.linux-x64 10.0.10","Microsoft.NetCore.App.Runtime.osx-arm64 10.0.10","Microsoft.NetCore.App.Runtime.osx-x64 10.0.10","Microsoft.NetCore.App.Runtime.win-arm 10.0.10","Microsoft.NetCore.App.Runtime.win-arm64 10.0.10","Microsoft.NetCore.App.Runtime.win-x64 10.0.10","Microsoft.NetCore.App.Runtime.win-x86 10.0.10","Microsoft.NetCore.App.Runtime.linux-arm 9.0.18","Microsoft.NetCore.App.Runtime.linux-arm64 9.0.18","Microsoft.NetCore.App.Runtime.linux-musl-arm 9.0.18","Microsoft.NetCore.App.Runtime.linux-musl-arm64 9.0.18","Microsoft.NetCore.App.Runtime.linux-musl-x64 9.0.18","Microsoft.NetCore.App.Runtime.linux-x64 9.0.18","Microsoft.NetCore.App.Runtime.osx-arm64 9.0.18","Microsoft.NetCore.App.Runtime.osx-x64 9.0.18","Microsoft.NetCore.App.Runtime.win-arm 9.0.18","Microsoft.NetCore.App.Runtime.win-arm64 9.0.18","Microsoft.NetCore.App.Runtime.win-x64 9.0.18","Microsoft.NetCore.App.Runtime.win-x86 9.0.18","Microsoft.NetCore.App.Runtime.linux-arm 8.0.29","Microsoft.NetCore.App.Runtime.linux-arm64 8.0.29","Microsoft.NetCore.App.Runtime.linux-musl-arm 8.0.29","Microsoft.NetCore.App.Runtime.linux-musl-arm64 8.0.29","Microsoft.NetCore.App.Runtime.linux-musl-x64 8.0.29","Microsoft.NetCore.App.Runtime.linux-x64 8.0.29","Microsoft.NetCore.App.Runtime.osx-arm64 8.0.29","Microsoft.NetCore.App.Runtime.osx-x64 8.0.29","Microsoft.NetCore.App.Runtime.win-arm 8.0.29","Microsoft.NetCore.App.Runtime.win-arm64 8.0.29","Microsoft.NetCore.App.Runtime.win-x64 8.0.29","Microsoft.NetCore.App.Runtime.win-x86 8.0.29"],"ingestedAt":"2026-07-20T23:44:02.730Z","slug":"CVE-2026-50659","body":"## Overview\n\nImproper encoding or escaping of output in .NET allows an authorized attacker to perform spoofing over a network.\n\n## Affected\n\n- `.net_10.0 >= 10.0.0 < 10.0.10`\n- `.net_8.0 >= 8.0.0 < 8.0.29`\n- `.net_9.0 >= 9.0.0 < 9.0.18`\n- `.net_framework_3.5 >= 3.5.0 < 2.0.50727.8983 & 3.0.30729.8978`\n- `.net_framework_3.5_and_4.7.2 >= 4.7.0 < 2.0.50727.9069 & 3.0.30729.9067 & 4.7.4143.0`\n- `.net_framework_3.5_and_4.8 >= 4.8.0 < 2.0.50727.9069 & 3.0.30729.9067 & 4.8.4803.0`\n- `.net_framework_3.5_and_4.8.1 >= 4.8.1 < 2.0.50727.9182 & 3.0.30729.9168 & 4.8.9339.0`\n- `.net_framework_4.6.2_4.7_4.7.1_4.7.2 >= 4.7.0 < 4.7.4143.0`\n- `.net_framework_4.8 >= 4.8.0 < 4.8.4803.0`\n- `.net_framework_4.8.1 >= 4.8.0.0 < 4.8.9340.0`\n- `visual_studio_2022_version_17.12 >= 17.12.0 < 17.12.22`\n- `visual_studio_2022_version_17.14 >= 17.14.0 < 17.14.36`\n- `visual_studio_2026_version_18.7 >= 18.0 < 18.7.4`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-50659)\n\nAffected packages:\n\n- `Microsoft.NetCore.App.Runtime.linux-arm >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.linux-arm64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.linux-musl-x64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.linux-x64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.osx-arm64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.osx-x64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.win-arm >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.win-arm64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.win-x64 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.win-x86 >= 10.0.0, <= 10.0.9`\n- `Microsoft.NetCore.App.Runtime.linux-arm >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.linux-arm64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.linux-musl-x64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.linux-x64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.osx-arm64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.osx-x64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.win-arm >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.win-arm64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.win-x64 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.win-x86 >= 9.0.0, <= 9.0.17`\n- `Microsoft.NetCore.App.Runtime.linux-arm >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.linux-arm64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.linux-musl-x64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.linux-x64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.osx-arm64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.osx-x64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.win-arm >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.win-arm64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.win-x64 >= 8.0.0, <= 8.0.28`\n- `Microsoft.NetCore.App.Runtime.win-x86 >= 8.0.0, <= 8.0.28`\n\nPatched in:\n\n- `Microsoft.NetCore.App.Runtime.linux-arm 10.0.10`\n- `Microsoft.NetCore.App.Runtime.linux-arm64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm 10.0.10`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.linux-musl-x64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.linux-x64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.osx-arm64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.osx-x64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.win-arm 10.0.10`\n- `Microsoft.NetCore.App.Runtime.win-arm64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.win-x64 10.0.10`\n- `Microsoft.NetCore.App.Runtime.win-x86 10.0.10`\n- `Microsoft.NetCore.App.Runtime.linux-arm 9.0.18`\n- `Microsoft.NetCore.App.Runtime.linux-arm64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm 9.0.18`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.linux-musl-x64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.linux-x64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.osx-arm64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.osx-x64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.win-arm 9.0.18`\n- `Microsoft.NetCore.App.Runtime.win-arm64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.win-x64 9.0.18`\n- `Microsoft.NetCore.App.Runtime.win-x86 9.0.18`\n- `Microsoft.NetCore.App.Runtime.linux-arm 8.0.29`\n- `Microsoft.NetCore.App.Runtime.linux-arm64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm 8.0.29`\n- `Microsoft.NetCore.App.Runtime.linux-musl-arm64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.linux-musl-x64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.linux-x64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.osx-arm64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.osx-x64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.win-arm 8.0.29`\n- `Microsoft.NetCore.App.Runtime.win-arm64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.win-x64 8.0.29`\n- `Microsoft.NetCore.App.Runtime.win-x86 8.0.29`\n\nSource: https://github.com/advisories/GHSA-74jp-vm22-8q8x","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}