CVE-2026-56855
Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh
- State
- Published
- Severity
- 7.5 High
- Published
- Sep 2, 2026
- Updated
- Sep 3, 2026
- Reserved
- Jun 23, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CISA-ADP |
Weaknesses
- CWE-770 Allocation of Resources Without Limits or Throttling
Affected Products
| Product | Versions |
|---|---|
golang.org/x/crypto/sshgolang.org/x/crypto |
|
References
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