CVE record
CVE-2026-56855
Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh
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.
CVE evidence
Known exploitation
Not listed in fetched KEV catalog
Absence from the fetched catalog does not establish that exploitation has not occurred.
Severity
high
CVSS 7.5 · CVSS_V3
Affected packages
1
Supported package records returned by OSV. Vendor and product names are not used to infer matches.
OSV package mapping
Affected open-source packages
| Package | Ecosystem | Fixed versions |
|---|---|---|
| golang.org/x/crypto | go | 0.56.0 |