Medium severity · published May 22, 2026
CVE-2026-39827
Invoking memory leak when rejecting channels can lead to DoS in golang.org/x/crypto/ssh
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
An authenticated SSH client that repeatedly opened channels which were rejected by the server caused unbounded memory growth, eventually crashing the server process and affecting all connected users. Rejected channels are now properly removed from the connection's internal state and released for garbage collection.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GO
golang.org/x/crypto/ssh · golang.org/x/crypto
before 0.52.0 · source: vendor
CR
Crypto · Golang
before 0.52.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39827
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-39827
Issue Tracking
https://go.dev/cl/781320
Issue Tracking
https://go.dev/issue/35127
Mailing List
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
Vendor Advisory
https://pkg.go.dev/vuln/GO-2026-5016
More from golang.org/x/crypto/ssh
10.0
CVE-2026-46595
Invoking VerifiedPublicKeyCallback permissions skip enforcement in golang.org/x/crypto/ssh
9.1
CVE-2026-39834
Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh
9.1
CVE-2026-39831
Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh
9.1
CVE-2026-39830
Invoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/ssh
7.5
CVE-2026-56855
Prevent DoS on deadlocked established channel in golang.org/x/crypto/ssh