{"api_version":"1","generated_at":"2026-09-03T03:55:44+00:00","cve":"CVE-2026-56855","urls":{"html":"https://cve.report/CVE-2026-56855","api":"https://cve.report/api/cve/CVE-2026-56855.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-56855","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-56855"},"summary":{"title":"Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh","description":"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.","state":"PUBLISHED","assigner":"Go","published_at":"2026-09-02 20:17:36","updated_at":"2026-09-02 20:17:36"},"problem_types":["CWE-770: Allocation of Resources Without Limits or Throttling"],"metrics":[],"references":[{"url":"https://groups.google.com/g/golang-announce/c/1y3fb2np35U","name":"https://groups.google.com/g/golang-announce/c/1y3fb2np35U","refsource":"security@golang.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://go.dev/issue/81317","name":"https://go.dev/issue/81317","refsource":"security@golang.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://go.dev/cl/826524","name":"https://go.dev/cl/826524","refsource":"security@golang.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://pkg.go.dev/vuln/GO-2026-6355","name":"https://pkg.go.dev/vuln/GO-2026-6355","refsource":"security@golang.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-56855","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56855","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"golang.org/x/crypto","product":"golang.org/x/crypto/ssh","version":"affected 0.56.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Will Mortensen","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"collectionURL":"https://pkg.go.dev","defaultStatus":"unaffected","packageName":"golang.org/x/crypto/ssh","product":"golang.org/x/crypto/ssh","programRoutines":[{"name":"channel.handlePacket"},{"name":"Dial"},{"name":"NewClientConn"},{"name":"NewControlClientConn"},{"name":"NewServerConn"}],"vendor":"golang.org/x/crypto","versions":[{"lessThan":"0.56.0","status":"affected","version":"0","versionType":"semver"}]}],"credits":[{"lang":"en","value":"Will Mortensen"}],"descriptions":[{"lang":"en","value":"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."}],"problemTypes":[{"descriptions":[{"description":"CWE-770: Allocation of Resources Without Limits or Throttling","lang":"en"}]}],"providerMetadata":{"dateUpdated":"2026-09-02T19:37:05.807Z","orgId":"1bb62c36-49e3-4200-9d77-64a1400537cc","shortName":"Go"},"references":[{"url":"https://go.dev/issue/81317"},{"url":"https://go.dev/cl/826524"},{"url":"https://groups.google.com/g/golang-announce/c/1y3fb2np35U"},{"url":"https://pkg.go.dev/vuln/GO-2026-6355"}],"title":"Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh"}},"cveMetadata":{"assignerOrgId":"1bb62c36-49e3-4200-9d77-64a1400537cc","assignerShortName":"Go","cveId":"CVE-2026-56855","datePublished":"2026-09-02T19:37:05.807Z","dateReserved":"2026-06-23T15:10:49.353Z","dateUpdated":"2026-09-02T19:37:05.807Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-02 20:17:36","lastModifiedDate":"2026-09-02 20:17:36","problem_types":["CWE-770: Allocation of Resources Without Limits or Throttling"],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"56855","Ordinal":"1","Title":"Prevent DoS on deadlocked established channel in golang.org/x/cr","CVE":"CVE-2026-56855","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"56855","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Prevent DoS on deadlocked established channel in golang.org/x/cr"}]}}}