CVE-2026-56855 | BDVDB-2026-367309 Detail

golang.org/x/cryptogolang.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.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact high. Attack vector: network.

Weaknesses#

CWE-770 Allocation of Resources Without Limits or Throttling

References#

Exploit#

No public exploit known

History#

Version 12026-09-02Record published in the CVE List.
Version 22026-09-03Most recent update recorded in the CVE List.

Published

Published: 2026-09-02
Last modified: 2026-09-03

Vendor information

Vendor: golang.org/x/crypto
Product: golang.org/x/crypto/ssh

All golang.org/x/crypto vulnerabilities

Score

7.5 High

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 43.1.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Not classified

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
< 0.56.0
Fixed
0.56.0

Scoring System

CVSS v4.0

Not available

CVSS v3.1

7.5 High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	None
Scope	Unchanged
Confidentiality	None
Integrity	None
Availability	High

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).