{"id":"CVE-2026-56855","summary":"Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh","details":"Previously, after a channel has been established, a malicious peer could send crafted messages that would deadlock the entire connection. Now, we handle all RFC 4254 channel messages; global requests are handled explicitly. Then, treat all other messages as a protocol error and tear the connection down instead of buffering and blocking.","aliases":["GO-2026-6355"],"modified":"2026-09-09T18:26:46.703840824Z","published":"2026-09-02T19:37:05.807Z","related":["openSUSE-SU-2026:11685-1","openSUSE-SU-2026:11691-1","openSUSE-SU-2026:11698-1","openSUSE-SU-2026:11704-1","openSUSE-SU-2026:11717-1","openSUSE-SU-2026:11727-1"],"database_specific":{"unresolved_ranges":[{"extracted_events":[{"fixed":"0.56.0"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"Go","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56855.json"},"references":[{"type":"WEB","url":"https://go.dev/cl/826524"},{"type":"WEB","url":"https://go.dev/issue/81317"},{"type":"WEB","url":"https://groups.google.com/g/golang-announce/c/1y3fb2np35U"},{"type":"WEB","url":"https://pkg.go.dev"},{"type":"WEB","url":"https://pkg.go.dev/vuln/GO-2026-6355"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56855.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56855"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/golang/crypto","events":[{"introduced":"0"},{"fixed":"86efde54dc7069251a8b007026c500d28e4239ce"}],"database_specific":{"cpe":"cpe:2.3:a:golang:crypto:*:*:*:*:*:go:*:*","extracted_events":[{"introduced":"0"},{"fixed":"0.56.0"}],"source":"CPE_RANGE"}}],"versions":["v0.55.0","v0.54.0","v0.53.0","v0.52.0","v0.51.0","v0.50.0","v0.49.0","v0.48.0","v0.47.0","v0.46.0","v0.45.0","v0.44.0","v0.43.0","v0.42.0","v0.41.0","v0.40.0","v0.39.0","v0.38.0","v0.37.0","v0.36.0","v0.35.0","v0.34.0","v0.33.0","v0.32.0","v0.31.0","v0.30.0","v0.29.0","v0.28.0","v0.27.0","v0.26.0","v0.25.0","v0.24.0","v0.23.0","v0.22.0","v0.21.0","v0.20.0","v0.19.0","v0.18.0","v0.17.0","v0.16.0","v0.15.0","v0.14.0","v0.13.0","v0.12.0","v0.11.0","v0.10.0","v0.9.0","v0.8.0","v0.7.0","v0.6.0","v0.5.0","v0.4.0","v0.3.0","v0.2.0","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-56855.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}