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CVE-2026-56855

Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh

Published: Sep 2, 2026Updated: Sep 4, 2026 Sources: CVE List NVDCWE-770
7.5HIGH
NVD MITRE
EPSS Score
0.4%
Top 69.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-770

Affected Products

golang.org/x/crypto
oss-projectaka golang x crypto, x/crypto
golang.org/x/crypto/sshLibrary
OSS Libraries / go
golang
oss-project·US
crypto
OSS Libraries

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://go.dev/issue/81317
go.dev
https://go.dev/cl/826524
go.dev
https://groups.google.com/g/golang-announce/c/1y3fb2np35U
groups.google.com
and 1 more references View all →

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