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CVE-2026-39834

Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh

Published: May 22, 2026Updated: May 28, 2026 Sources: CVE List NVDCWE-190
NVD MITRE
9.1CVSSCRITICAL
EPSS Score
0.4%
Top 69.2%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:HA: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:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-190

Affected Products

golang.org/x/crypto/sshgolang.org/x/crypto
Library
OSS Libraries / go
cryptogolangOSS Libraries
golang.org/x/cryptooss-projectOSS Librariesaka x/crypto, golang x crypto
golangoss-projectUSOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
View detailed technique mapping

References

https://go.dev/issue/79567
go.dev
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
groups.google.com
https://go.dev/cl/781663
go.dev
and 1 more references View all →

Timeline

Published
May 22, 2026
Last Updated
May 28, 2026

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