{"schema_version":"1.3.1","id":"GO-2026-5038","modified":"2026-06-02T21:39:47Z","published":"2026-06-02T21:39:47Z","aliases":["CVE-2026-42504"],"summary":"Quadratic complexity in WordDecoder.DecodeHeader in mime","details":"Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.","affected":[{"package":{"name":"stdlib","ecosystem":"Go"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.25.11"},{"introduced":"1.26.0-0"},{"fixed":"1.26.4"}]}],"ecosystem_specific":{"imports":[{"path":"mime","symbols":["WordDecoder.DecodeHeader"]}]}}],"references":[{"type":"REPORT","url":"https://go.dev/issue/79217"},{"type":"FIX","url":"https://go.dev/cl/774481"},{"type":"WEB","url":"https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw"}],"credits":[{"name":"p4p3r (https://hackerone.com/p4p3r_hak) "}],"database_specific":{"url":"https://pkg.go.dev/vuln/GO-2026-5038","review_status":"REVIEWED"}}