{"cve":"CVE-2026-56855","nvd":{"published":"2026-09-02T20:17:36.397","modified":"2026-09-04T16:34:56.823","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-770"],"references":["https://go.dev/cl/826524","https://go.dev/issue/81317","https://groups.google.com/g/golang-announce/c/1y3fb2np35U","https://pkg.go.dev/vuln/GO-2026-6355"],"products":["golang:crypto"],"source":"nvd","synced_at":"2026-10-19T22:50:50.842544443+00:00"},"epss":{"cve":"CVE-2026-56855","score":0.005,"percentile":0.4287,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GO-2026-6355","url":"https://osv.dev/vulnerability/GO-2026-6355","summary":"Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh","modified":"2026-09-24T10:41:42.556134596Z","packages":[{"ecosystem":"Go","name":"golang.org/x/crypto","purl":"pkg:golang/golang.org/x/crypto","ranges":["<0.56.0"],"fixed":["0.56.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}