{"action":"Upgrade stdlib to 1.25.13 or later.","affected":[{"fixed":"1.25.13","introduced":"0"},{"fixed":"1.26.6","introduced":"1.26.0-0"},{"introduced":"1.27.0-0"}],"component":"stdlib","cve_ids":["CVE-2026-39821"],"ecosystem":"Go","exploited":false,"fixed_versions":["1.25.13","1.26.6","1.27.0-rc.3"],"id":"tcs_01M5JHHCZ9RJKEKRBSTQRADW4P","modified_at":"2026-10-16T10:42:05.164302476Z","published_at":"2026-05-22T02:46:43Z","references":["https://osv.dev/vulnerability/GO-2026-5026","https://go.dev/cl/767220","https://go.dev/issue/78760","https://groups.google.com/g/golang-announce/c/iI-mYSI0lu8","https://groups.google.com/g/golang-announce/c/94pEornpRlI"],"severity":{"label":"critical","score":9.6},"sources":[{"source":"osv","source_id":"GO-2026-5026","url":"https://osv.dev/vulnerability/GO-2026-5026"},{"source":"nvd","source_id":"CVE-2026-39821","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39821"}],"summary":"Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna"}