{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-56855", "assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "state": "PUBLISHED", "assignerShortName": "Go", "dateReserved": "2026-06-23T15:10:49.353Z", "datePublished": "2026-09-02T19:37:05.807Z", "dateUpdated": "2026-09-03T14:14:40.169Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc", "shortName": "Go", "dateUpdated": "2026-09-02T19:37:05.807Z"}, "title": "Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh", "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."}], "affected": [{"vendor": "golang.org/x/crypto", "product": "golang.org/x/crypto/ssh", "collectionURL": "https://pkg.go.dev", "packageName": "golang.org/x/crypto/ssh", "versions": [{"version": "0", "lessThan": "0.56.0", "status": "affected", "versionType": "semver"}], "programRoutines": [{"name": "channel.handlePacket"}, {"name": "Dial"}, {"name": "NewClientConn"}, {"name": "NewControlClientConn"}, {"name": "NewServerConn"}], "defaultStatus": "unaffected"}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-770: Allocation of Resources Without Limits or Throttling"}]}], "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"}], "credits": [{"lang": "en", "value": "Will Mortensen"}]}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-770", "lang": "en", "description": "CWE-770 Allocation of Resources Without Limits or Throttling"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-09-03T14:13:54.397574Z", "id": "CVE-2026-56855", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-03T14:14:40.169Z"}}]}}

{}

{"affected": [{"affectedData": [{"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"}]}], "source": "security@golang.org"}], "cveTags": [], "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."}], "id": "CVE-2026-56855", "lastModified": "2026-09-02T20:17:36.397", "metrics": {}, "published": "2026-09-02T20:17:36.397", "references": [{"source": "security@golang.org", "url": "https://go.dev/cl/826524"}, {"source": "security@golang.org", "url": "https://go.dev/issue/81317"}, {"source": "security@golang.org", "url": "https://groups.google.com/g/golang-announce/c/1y3fb2np35U"}, {"source": "security@golang.org", "url": "https://pkg.go.dev/vuln/GO-2026-6355"}], "sourceIdentifier": "security@golang.org", "vulnStatus": "Received"}

{}

{"created": "2026-09-03T09:45:03.890235+00:00", "updated": "2026-09-03T09:45:03.890241+00:00", "vendors": [], "weaknesses": ["CWE-667"]}