CVE-2026-39830criticalCWE-772

CVE-2026-39830: critical vulnerability in golang.org/x/crypto/ssh

Invoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/ssh

Published 22 May 2026 · Updated 18 Sep 2026

28Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 9.1epss 0.7%

exploitation probability

0.7%top 48% of all CVEs

observed exploitation

nono source reports it

A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded.

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

Affected products

golang.org/x/crypto · golang.org/x/crypto/ssh

Related CVEs — golang.org/x/crypto/ssh

In the same product, most dangerous first.

CVE-2024-45337CRITICALMisuse of connection.serverAuthenticate may cause authorization bypass in golang.org/x/cryptoEPSS 3.2%CVE-2025-22869HIGHPotential denial of service in golang.org/x/cryptoEPSS 0.9%CVE-2026-39834CRITICALInvoking infinite loop on large channel writes in golang.org/x/crypto/sshEPSS 0.6%CVE-2025-58181MEDIUMUnbounded memory consumption in golang.org/x/crypto/sshEPSS 0.6%CVE-2026-46595CRITICALInvoking VerifiedPublicKeyCallback permissions skip enforcement in golang.org/x/crypto/sshEPSS 0.6%CVE-2026-39835MEDIUMInvoking server panic during CheckHostKey/Authenticate in golang.org/x/crypto/sshEPSS 0.5%

References