{"action":"Upgrade MessagePack to 2.5.301 (2.x) or 3.1.7 (3.x) or later.","affected":[{"fixed":"2.5.301","introduced":"0"},{"fixed":"3.1.7","introduced":"3.0"}],"component":"MessagePack","cve_ids":["CVE-2026-48509"],"ecosystem":"NuGet","epss":0.00416,"exploited":false,"fixed_versions":["2.5.301","3.1.7"],"ghsa_id":"GHSA-2f33-pr97-265q","id":"tcs_01M5N85QJXJEDE26S64XEFXYVB","modified_at":"2026-06-25T19:11:29.503314Z","published_at":"2026-06-25T18:52:46Z","references":["https://osv.dev/vulnerability/GHSA-2f33-pr97-265q","https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-2f33-pr97-265q","https://nvd.nist.gov/vuln/detail/CVE-2026-48509","https://github.com/MessagePack-CSharp/MessagePack-CSharp"],"severity":{"label":"critical","score":9.1},"sources":[{"source":"osv","source_id":"GHSA-2f33-pr97-265q","url":"https://osv.dev/vulnerability/GHSA-2f33-pr97-265q"},{"source":"nvd","source_id":"CVE-2026-48509","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48509"}],"summary":"MessagePack-CSharp: ASP.NET Core MessagePackInputFormatter defaults to TrustedData for HTTP request bodies"}