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CVE-2026-56855

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-56855

Severity

7.5

High

CVSS V3

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Summary

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.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-56855
  • https://pkg.go.dev/vuln/GO-2026-6355
  • https://go.dev/cl/826524
  • https://go.dev/issue/81317
  • https://groups.google.com/g/golang-announce/c/1y3fb2np35U
  • https://pkg.go.dev
  • https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56855.json

Affected packages

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