{"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-2026-48516"],"ecosystem":"NuGet","epss":0.00405,"exploited":false,"fixed_versions":["2.5.301","3.1.7"],"ghsa_id":"GHSA-q2h6-ghwm-5qm8","id":"tcs_01M5N8XEFN26FHNVQ0G8C4YZSY","modified_at":"2026-06-25T21:56:26.281367Z","published_at":"2026-06-25T21:29:39Z","references":["https://osv.dev/vulnerability/GHSA-q2h6-ghwm-5qm8","https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-q2h6-ghwm-5qm8","https://nvd.nist.gov/vuln/detail/CVE-2026-48516","https://github.com/MessagePack-CSharp/MessagePack-CSharp"],"severity":{"label":"high","score":7.5},"sources":[{"source":"osv","source_id":"GHSA-q2h6-ghwm-5qm8","url":"https://osv.dev/vulnerability/GHSA-q2h6-ghwm-5qm8"},{"source":"nvd","source_id":"CVE-2026-48516","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48516"}],"summary":"MessagePack-CSharp: InterfaceLookupFormatter bypasses collision-resistant comparer settings"}