{"id":"GO-2026-6612","aliases":["BIT-golang-2026-78663","CVE-2026-78663"],"title":"Double flow control refund on HTTP/2 server streams in net/http","titleSource":"OSV","descriptionSource":"OSV","description":"The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.","severity":"unknown","score":null,"published":"2026-10-08T22:31:09.000Z","modified":"2026-11-14T13:12:14.440Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Go","name":"stdlib","sources":[{"name":"OSV · GO-2026-6612","url":"https://osv.dev/vulnerability/GO-2026-6612"}],"ranges":[{"events":[{"introduced":"0"},{"fixed":"1.26.9"}],"type":"SEMVER"}],"versions":[],"fixed":["1.26.9"]},{"ecosystem":"Go","name":"stdlib","sources":[{"name":"OSV · GO-2026-6612","url":"https://osv.dev/vulnerability/GO-2026-6612"}],"ranges":[{"events":[{"introduced":"1.27.0-0"},{"fixed":"1.27.2"}],"type":"SEMVER"}],"versions":[],"fixed":["1.27.2"]},{"ecosystem":"Go","name":"golang.org/x/net","sources":[{"name":"OSV · GO-2026-6612","url":"https://osv.dev/vulnerability/GO-2026-6612"}],"ranges":[{"events":[{"introduced":"0"},{"fixed":"0.60.0"}],"type":"SEMVER"}],"versions":[],"fixed":["0.60.0"]}],"sourceAffected":[],"references":["https://go.dev/cl/847187","https://go.dev/cl/847310","https://go.dev/issue/81743","https://groups.google.com/g/golang-announce/c/U2fTuyDJznI","https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs"],"sources":[{"name":"OSV","id":"GO-2026-6612","modified":"2026-11-14T13:12:14.440833902Z","url":"https://osv.dev/vulnerability/GO-2026-6612"}],"assessments":[],"products":[],"remediation":[],"observedAt":"2026-11-14T15:05:10.589Z","kev":{"status":"not-listed","checkedAt":"2026-11-15T01:30:33.103Z"},"coverage":[{"source":"NVD","status":"available","checkedAt":"2026-11-14T00:50:45.180Z","attemptedAt":"2026-11-14T00:50:45.180Z"},{"source":"GHSA","status":"no-result","checkedAt":"2026-11-14T00:40:32.839Z","attemptedAt":"2026-11-14T00:40:32.839Z"},{"source":"EUVD","status":"available","checkedAt":"2026-11-14T00:40:33.578Z","attemptedAt":"2026-11-14T00:40:33.578Z"},{"source":"EPSS","status":"available","checkedAt":"2026-11-14T00:40:31.945Z","attemptedAt":"2026-11-14T00:40:31.945Z"}],"evidence":[{"source":"FIRST EPSS","id":"CVE-2026-78663","url":"https://www.first.org/epss/","probability":0.00858,"percentile":0.58989,"date":"2026-11-13","checkedAt":"2026-11-14T00:40:31.945Z"},{"source":"ENISA EUVD","id":"EUVD-2026-95427","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-95427","modified":"Oct 9, 2026, 4:42:50 PM","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","checkedAt":"2026-11-14T00:40:33.578Z"},{"source":"NVD","id":"CVE-2026-78663","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-78663","modified":"2026-10-09T17:16:49.420","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","checkedAt":"2026-11-14T00:50:45.180Z"}],"aiSummary":null}