CVE-2026-56855

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 breakdown

Affected products

• Golang / crypto0.56.0
• golang.org/x/crypto / golang.org/x/crypto/ssh0 – 0.56.0

References

• MISChttps://go.dev/issue/81317
• MISChttps://go.dev/cl/826524
• MISChttps://groups.google.com/g/golang-announce/c/1y3fb2np35U
• MISChttps://pkg.go.dev/vuln/GO-2026-6355